grumpyvette

"Whats with the dual x-pipes? I dont see what it acomplishes?" first let me point out thats not my exhaust in the pic, but mine is layed out very similar but useing these http://store5.yimg.com/I/exhaustpros_1775_19440103 DUAL (X) 3" pipes with a smoother curve exiting my collectors,it makes it sounds better, lower,in tone and it growls and its meaner,sounding, when combined with the vortec cones, it lowers back pressure in the collectors to what open headers read when the engine RPMS and it allows me to run no mufflers on a light weight exhaust without getting tickets on the street, hey it might not work for everyone but I like it!

a few other places http://www.acdelco.com/html/pi_plugs_ident.htm http://www.autolite.com/framer.cgi?page=http://www.autolite.com/products/racing.htm http://members.uia.net/pkelley2/sparkplugreading.html http://www.atlanticjetsports.com/_techtalk/00000005.htm http://www.strappe.com/plugs.html http://www.babcox.com/editorial/cm/cm59910.htm http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf http://www.nightrider.com/biketech/spkplghnbook.htm http://www.tsrsoftware.com/sparkplug.htm http://www.gnttype.org/techarea/engine/plugs.html http://www.dansmc.com/sparkplugs1.htm http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp2.asp http://www.pajjakid.com/ubipa/sparkplugs.htm http://www.edelbrock.com/automotive/sparkplugs.html http://www.bullittarchive.com/Maintenance/Sparkplugoverview/ http://www.powerarc.com/sparkplug.htm http://www.carcraft.com/techarticles/64378/ http://www.wakularacing.com/TechnicalInfo.htm http://www.geocities.com/MotorCity/Flats/3877/spark.html heres a few tips new corvette guys don,t always know (1)theres several removable panels near the suspension that make spark plug accsess much easier after they are removed (2) use a 2 foot long section of 3/8" fuel line slipped /forced over the end of the spark plug as a hand guide when placeing and removing plugs into the threads once they are loose, this can be spun to turn the plugs from many odd angles (3)theres several tools designed to make life easier http://store.yahoo.com/squaredrive/sw-1001.html http://store.yahoo.com/squaredrive/sw-1001.html (4) long extensions with a universal 5/8" sparkplug socket can be used in many cases (5) if it takes over an hour your doing something very wrong

well according to the manufacturer the dual or triple layer synthetic cover is good for approximately 10 years http://coverit.com/technical/tech_cover.html http://coverit.com/technical/compare.html and its not the cheap nylon/rayon/tafata tent cover like SEARS and COSTCO SELL

heres two metal frame synthetic car shelters, how many of you have purchased or would purchase one of these for your car. the reason Im asking is that I may want to get a distributorship as Ive found them to be a really good tool to allow working on my corvettes and feel they are priced fairly according to the manufacturer the dual or triple layer synthetic cover is good for approximately 10 years http://coverit.com/technical/tech_cover.html http://coverit.com/technical/compare.html http://coverit.com/technical/tech_anchor.html http://coverit.com/technical/tech_faq.html and its not the cheap nylon/rayon/tafata tent cover like SEARS and COSTCO SELL YOUR FEEDBACK/INPUT IS WANTED GUYS

some of you have asked for advise on setting up your data base, for info you need to build and race successfuly well what I did was set up about 50 to 60 catagories and sub catagories and everytime I got any data,over the years, links,sites,essays,notes,ETC. I just file it under the most closely matching catagory, catagories like blocks heads flow #s cranks machine work, tuneing data carbs cam specs pistons rods oil pans oil control heat treating coatings bbc combos sbc combos pontiac combos caddy combos hemi combos transmissions rear suspensions tires suspension mods ballancing oil fuel assembly mods torque specs engine weights/dimensions safety equip roll cages light weight components hood scoops welding detonation octane boosters calculator formulas rings pistons coatings parts suppliers manufacturers better combos machine shop costs corvette related fiberglas/carbon fiber parts turbos superchargers valves dyno graphs exhaust/headers fuel injection intakes ETC. use your own priorities and needs I print out and save a hard copy of the more important data for a copy because web info comes and goes from the web. I use (MICROSOFT WORD) to save important documents, I make lists of links and sub links I keep updated PHONE NUMBER LISTs,WEB SITE LISTS, for SUPPLIERS AND MANUFACTURES

first thing you need to understand is that DYNO SOFTWARE is a good tool for finding trends, and pointing out areas that need improvements but LOUSY for predicting EXACT DYNO RESULTS. Ive got 5 totally differant software programs the easiest to use is DD-2000 ABOUT $40 http://www.autorepairmanuals.biz/site/573683/page/189725 engine analyzer is a good value (about $110) http://www.auto-ware.com/software/ea/ea.htm the BEST RESULTS ARE FROM ENGINE ANALYZER PROgives good info but its a P.I.T.A. to work with http://www.auto-ware.com/software/eap/eap.htm you might want to look over these sites before spending money http://racingdownloads.com/ http://www.virtualengine2000.com/ http://www.auto-ware.com/ http://www.motionsoftware.com/ http://www.performancetrends.com/ http://www.rapidline.com/ http://users.erols.com/srweiss/index.html

we have all heard it, " you need massive low rpm tq" "you need a screaming high rpm hp peak" well heres some info, More in-depth description: http://www.revsearch.com/dynamometer/torque_vs_horsepower.html http://www.dynacam.com/Product/Torque_vs__Horsepower/torque_vs__horsepower.html http://vettenet.org/torquehp.html http://auto.howstuffworks.com/horsepower4.htm http://homepage.mac.com/dgiessel/engine/hpvstq.html first thing to keep in mind is that theres no such "thing" as horsepower, horsepower is a mathmatical formula for the RATE at which TORQUE can be applied the formula for hp is (tq x rpm/5252=hp example 450 ft lbs of torque at 3000rpm=257hp 450 ft lbs of torque at 6000rpm=514hp because the torque at the higher rpm useing gearing can be applied faster here read this http://www.69mustang.com/hp_torque.htm http://www.ubermensch.org/Cars/Technical/hp-tq/ http://vette.ohioracing.com/hp.html where most guys go wrong is in not correctly matching the cars stall speed and gearing to the cars tq curve, if you mod the engine for increased high rpm performance but fail to also match the stall speed and gearing to that higher rpm tq curve much of the potential improvement is wasted. example in the close to stock engine above, the engine should be geared to stay in the 3500rpm-5000rpm range for max acceleration (lower in the rpm range if mileage is a big factor) in the moded engine above the rpm range moved to 4000rpm-6500rpm requireing differant rear gears and slightly higher stall speeds to gain max acceleration in the same car, you should readily see that a trans that shifts at 5000rpm will work in the first example but would waste most of the power curve in the second example,where shifting at 6500rpm under full power acelleration would make more sence. a 3.08 rear gear and 700r4 trans matches the first example well but it would take a swap to a 3.73-4.11 gear to allow the engine in the second example to keep its most effective power band matching that second power curve well. links youll need to figure out correct rear gear ratios http://www.miata.net/garage/tirecalc.html http://www.wallaceracing.com/reargear.htm http://users.erols.com/srweiss/calcmph.htm http://users.erols.com/srweiss/calcrpm.htm http://users.erols.com/srweiss/calcrgr.htm http://www.prestage.com/Car+Math/Ge...io/default.aspx http://www.geocities.com/z28esser/speed.html http://server3003.freeyellow.com/gparts/speedo.htm http://www.pontiacracing.net/trannyratios.htm http://www.tciauto.com/tech_info/gear_ratios.htm

"Miracle oils" in an engine http://texassynthetics.com/aftermarketadditives.htm http://www.bestsyntheticoil.com/amsoil/snakeoil.shtml http://www.cortecvci.com/whats_new/announcements/pr-010503.html http://neptune.spacebears.com/cars/legal/oiladd.html http://www.bobistheoilguy.com/videos.html

my corvette has an exhaust that currently looks similar to this but with smoother bends on the (X)s that uses no mufflers and exits pointing at the contact point between the rear tires and the pavement,and I have those vortec cones NOT in the collectors but in a slip on short extension on the exhaust exits, it helps the noise but does not seem to have any restriction or loss of power when they are installed

http://store.yahoo.com/exhaustpros/hustxpi.html http://store.yahoo.com/exhaustpros/magmanbenypi.html http://www.spiralturbobaffles.com/ http://www.secureperformanceorder.com/dynatechdragstore/vortex.cfm http://search.ebay.com/search/search.dll?query=header+flanges&newu=1&krd=1?keyword=header+flanges http://www.racerpartswholesale.com/flomstr1e.htm http://www.ssheaders.com/Collectors.htm http://www.burnsstainless.com/MergeCollectors/mergecollectors.html http://www.cachassisworks.com/header.htm http://www.holley.com/HiOctn/ProdLine/Products/ES/ESHHA/SplitFlow.html http://www.holley.com/HiOctn/ProdLine/Products/ES/ESHHA/Cutaway.html http://www.holley.com/HiOctn/ProdLine/Products/ES/ESHHA/HPipe.html http://store.summitracing.com/section.asp?d=8&s=577 btw http://www.grapeaperacing.com/GrapeApeRacing/tech/exhausttubesizes.cfm these should be considered MINIMUMS

is it possiable to post a picture of the dyno graph? those numbers look lower than normal (keep in mind guys that 317hp at the rear wheels is approximately 400 flywheel hp)

just a bit of info! I have NEVER seen an intake that had ports exactly match the heads I was useing,THEY ALL require at least minor port matching, and while there are some that are better that others in this respect, I think your fooling yourself if you think you can bolt any intake to a set of cylinder heads and expect that all the port entrances and water ports will be exact matchs. Ill agree that Ive got some really low quality castings from some sources at times, yet they frequently are also well done, they vary a good deal from year to year and model to model, thats where the guy assembling the engine comes into play his job is to match, and fit and adjust the parts so they work correctly as a well thought out combo, not a group of parts thrown together and expected to work, right out of the box,its fairly easy to pick up an aditional 20hp-60hp just doing easy but time consuming things like port matching the intakes, porting plenums and runners, useing carb spacers,pocket porting the heads,back cutting valves,useing differant ratio rockers, adjusting rocker geometry,fitting custom length header collectors, correctly clearance/ballance or finish the parts,add windage screens and other minor tweaks to the combo. WHILE NO ONE MODIFICATION SHOWS A HUGE IMPROVEMENT BY ITSELF , the COMBO HAS A VERY NOTICABLE EFFECT ON THE TOTAL POWER! the cost of parts that that work was pre-done by the manufacturers to match YOUR EXACT COMBO, would be cost prohibitive to most rodders, THATS WHY THE GUYS WHO TAKE THE TIME TO UNDERSTAND THE CONCEPTS OF WHATS HAPPENING IN THE ENGINE AND DO THE TWEAKS TO IMPROVE THE EFFICIENCY TEND TO WIN THE RACES, the bottom line is that a correctly built combo requires carefully matched parts designed to work at the SAME HP and RPM levels,MISS-MATCHED COMBOS DON,T TEND TO REACH THIER POTENTIAL,and BADLY MISS-MATCHED PARTS WILL TEND TO WORK AGAIST EACH OTHER AND COST YOU HP! FACTORY PRODUCED CARS AND PARTS ,DO NOT HAVE MAX PERFORMANCE AS THE MAIN GOAL, LOW PRODUCTION COST,EASE OF ASSEMBLY,EMISSIONS TESTING,CUSTOMER COMFORT, LOW PRICE, RELIABILITY all are HIGHER PRIORITIES!, CAMS AND GEARING TAKE AN ESPECIALLY HARD HIT ,AS MILEAGE, EMISSIONS,AND NOISE LEVELS FAR EXCEED, RAW PERFORMANCE AS GOAL IN MOST CARS port matching ALONE is rarely worth more than a few hp,simply because the ports are rarely more than 1/8" off matching and frequently even less, that does not make the mod worthless, but port matching combined with a pocket port on the cylinder heads and a back cut on the valves to increase low lift flow it becomes a PART of the whole mod and as such helps flow, the combo of mods DOES help and IVE seen just those mods give 15hp-25hp(mostly at peak rpms)

short answer? a good synthetic 10w30 or 15w40 will suit almost all engines well first you should realise that the OIL system does much of the engines cooling and a 7-8 qt baffled oil pan will normally absorb and cool the engine a great deal more than a 5 quart oil pan, due to both the larger oil supply and the larger surface area on that larger oil pan thats outer surface has a greater area expossed to the cool air flowing under the car that will normally be well over 120 degrees cooler than the oil inside that oil pan. adding a 8qt oil pan helps cool the engine a great deal, so much in fact that the 10.5qt custom oil pan on my corvette require the use of a 190f thermostat just to allow my oil to get to the minimum 215f degs necessary to burn off the moisture that sometimes accumulates in a non-running engine! ead this over carefully IVE POSTED MOST OF THIS BEFORE BUT IT FITS HERE AS A SOURCE OF INFO FOR THE NEWER GUYS the thinner the oil the faster it flows, the faster it gets to the surfaces that need the oil film, and the easier it is for the oil to flow thru the clearances,the engines operating temp. the engines clearances,and the oils thermal limits plus the engines ability to maitain sufficiant oil pressure and volume over the engine entire operating range effects the best oil choice. since mineral and SYNTHETIC OILS in the 10w30 or 10w-40 range are the standard for most engines thats what the clearances are set up for in most engines I found this diagram I find it interesting but all the data I've seen before I saw this diagram and which I trust considerably more than this diagram tends to point to slightly higher average temperatures being ideal. I have repeatedly said that your oil temp should keep above 215° to allow moisture to burnout of the oil and that your coolant temp should stay in the 180-220 range, remember OIL IS THE MAIN LIQUID CARRIER OF HEAT AWAY FROM THE RINGS,BEARINGS,ROCKERS,SPRINGS,AND PISTONS, AND ITS OIL RUNNING DOWN THE INNER BLOCK SURFACES THAT ALLOWS THAT HEAT ABSORBED BY THE OIL TO TRANSFER TO THE BLOCK AND COOLANT http://www.melling.com/highvol.html http://www.melling.com/engoil.html here this might help read this over carefully IVE POSTED MOST OF THIS BEFORE BUT IT FITS HERE AS A SOURCE OF INFO FOR THE NEWER GUYS http://www.melling.com/highvol.html http://www.melling.com/engoil.html ok lets look at a few things, pressure is the result of a resistance to flow , no matter how much oil is put out by the oil pump there is almost no pressure unless there is a resistance to that oil flow and the main resistance is from oil trying to flow through the bearing surface clearances and once the pumps output pressure exceeds the engines ability to accept the oilflow at the max pressure the oil return system/bypass spring allows the oil circles back through the pump ,now the amount of oil flow necessary to reach the furthest parts in the engine from the oil pump does not go up in direct relation to rpm, but it instead increases with rpm at a steadly increaseing rate that increases faster than the engine rpm due to centrifugal force draining the oil from the rods as they swing faster and faster since energy increases with the square of the velocity the rate of oil use goes up quite a bit faster due to the greatly increased (G-FORCES) pulling oil from the rod bearings over 5000rpm going to 8000rpm than the rate of oil flow increases from 2000 rpm to 5000rpm (the same 3000rpm spread) and remember the often stated (10 lbs per 1000rpm)needs to be measured at the furthest rod and main bearing from the pump not at the pump itself, next lets look at the oil flow itself, you have about 5-6 quarts in an average small block now the valve covers never get and hold more than about 1/3 to 2/3 of a quart each even at 8000 rpm (high speed photography by SMOKEY YUNICK doing stock car engine research with clear plastic valve covers prove that from what Ive read) theres about 1 quart in the lifter gallery at max and theres about 1 quart in the filter and in the oil passages in the block, that leaves at least 2 quarts in the pan at all times and for those that want to tell me about oil wrapped around the crankshaft at high rpms try squirting oil on a spinning surface doing even 2000rpm (yes thats right its thrown off as fast as it hits by centrifugal force, yes its possiable for the crankshaft WITHOUT A WINDAGE SCREEN to keep acting like a propeler and pulling oil around with it in the crank case but thats what the wrap around style milodon type windage screen is designed to stop)the only way to run out of oil is to start with less than 4 quarts or to plug the oil return passages in the lifter gallery with sludge or gasket material! now add a good windage tray and a crank scrapper and almost all the oil is returned to the sump as it enters the area of the spinning crankshaft! forming a more or less endless supply to the oil pump, BTW almost all pro teams now use DRY SUMP SYSTEMS WITH POSITIVE DISPLACEMENT GERATOR PUMPS that are 3,4,or 5 stage pumps each section of which has more voluum than a standard voluum oil pump because its been found total oil control is necessary at high rpms to keep bearings cool and lubed NOW I POSTED THIS BEFORE BUT IT NEEDs REPEATING ok look at it this way,what your trying to do here is keep an pressureized oil film on the surface of all the bearings to lube and cool them and have enough oil spraying from the rod and main bearing clearances to lube the cam and cylinder walls/rings. now a standard pump does a good job up to 5000rpm and 400 hp but above 6000rpm and 400hp the bearings are under more stress and need more oilflow to cool and because the pressure on the bearings is greater you need higher pressures to maintain that oilfilm.lets look at the flow verus pressure curve. [color:"red"] since oil is a liquid its non-compressable and flow will increase with rpm up to the point where the bypass circuit starts to re-route the excess flow at the point were the pressure exceeds the bypass spring pressure. but the voluum will be equal to the pumps sweep voluum times the rpm of the pump, since the high voluum pump has a sweep voluum 1.3-1.5 times the standard pump voluum it will push 1.3-1.5 times the voluum of oil up to the bypass cicuit cut in point,that means that since the engine bearings leakage rate increases faster as the rpms increase because the clearances don,t change but the bleed off rate does that the amount of oil and the pressure that it is under will increase faster and reach the bypass circuit pressure faster with the high voluum pump. the advantage here is that the metal parts MUST be floated on that oil film to keep the metal parts from touching/wearing and the more leakage points the oil flows by the less the voluum of oil thats available for each leakage point beyond it and as the oil heats up it becomes easier to push through the clearences.now as the rpms and cylinder preasures increase in your goal to add power the loads trying to squeeze that oil out of those clearances also increase. ALL mods that increase power either increase rpms,cylinder preasures or reduce friction or mechanical losses. there are many oil leakage points(100) in a standard chevy engine. 16 lifter to push rod points 16 pushrod to rocker arm points 32 lifter bores 16 x 2 ends 10 main bearing edges 9 cam bearing edges 16 rod bearing edges 2 distributor shaft leaks 1 distributor shaft to shim above the cam gear(some engines [/color] that have an oil pressure feed distributor shaft bearing.) so the more oil voluum the better,(AS LONG AS ITS TOTALLY UNDER CONTROL ON BOTH THE PRESSURE AND RETURN/SCAVAGEING SIDES OF THE SYSTEMchevy did an excelent job in the design but as the stresses increase the cooling voluum of the extra oil available from the larger pump helps to prevent lubracation delivery failure, do you need a better pump below 5000rpm or 400hp (no) above that level the extra oil will definitely help possiable deficient oil flow and bearing cooling and a simple increase in pressure does not provide a big increase in voluum that may be necessary to keep that oil film in the correct places at the correct voluum at all times.the stock system was designed for a 265cid engine in a passenger car turning a max of about 6000 rpm but only haveing the stress of under 300hp transmitted to the bearings, Im sure the orriginal designers never thought that the sbc or bbc would someday be asked to on occasion hold up to 450-800hp and 6000-8000 rpm.nore did they forsee valvesprings that placed 500lbs and up loads on the lifters and the use of over 9 to 1 compression ratios in the original design so the oil voluums and pressures necessary to cool those valve springs and bearings at those stress levels were never taken into account for that either. Continued (oil Pan/pump) the oil pump can only pump as much oil as the engine clearances allow at the max pressure that the oil pump bye -pass circuit will allow, and no more. for your idea to be correct (which it could be under some conditions)the oil flow through the engine clearances would need to be so great that the pump turning at 3500rpm,7000rpm engine speed(remember the pump spins 1/2 the speed the crank does)and most likely pumping at max pressure could lower the oil level to the point that the pick-up becomes uncovered or a vortex as you call it forms and the pump starts sucking air. now under hard acceleration it is very possiable for the pickup on ANY oil pump to to become uncovered in a oil pan that has less than 5qt capacity and with no oil control baffles as the oil rushes to the rear of the oil pan if the pick-up is located in mid pan or under hard brakeing if the pick-up is located at the rear of the pan on a non- oil baffle controlled pan. I will grant you that it is possiable for ANY oil pump to pump a good amount of oil into the lifter gallery at high rpms IF THE OIL RETURN PASSAGES IN THE HEADS AND LIFTER GALLERY ARE BLOCKED, preventing its normal return to the crankcase , but running a high volume oil pump will have little or nothing to do with how much oil is in the pan if the engines drain back holes are clear and your useing a milodon style windage screen. I have several times had that same complaint about lack of oil pressure under acceleration but it is caused by a non-baffled pan or the pickup mounted so close to the pan bottom that the pump cant get a good intake flow, if you carefully check youll find that on a dyno runs it seldom happens,because the oil is constantly removed by the windage screen is returned to the sump, most of the oil pumped into the system exits at the rod and main bearing clearances or at the cam bearings and from the lifter bores lower ends, its not the constant oil flow or lack of oil into the rocker arms that has the big effect on total oil flow as SMOKEY YUNICKS PHOTOGRAPIC RESEARCH PROVED YEARS AGO,its the oil flowing from the bearings and lifters and that oil flow is quickly returned to the sump by a windage screen scrapeing it off the spinning crank and rods as the spinning assembly passes over the windage screen. in effect most of the oil in an engine works like your timeing chain in that it constantly cycles top to botton and back never getting higher than the cam bearing lifter area. now what does quite frequently happen is that the guys installing a high volume oil pump just swap out the standard pump, reinstall the stock or simular pick-up and bolt on the pan with the pick-up in the stock possition on the oil pump. the stock pick-up is mounted about 3/8" off the pan bottom,the high volume pump is normally equiped with impeller gears about .3 inches longer than stock, the high volume pump body is that much lower in the pan, resultting in the pick-up being only about 1/8" from the pan bottom. the result is that on a normal chevy oil pump pick-up this leave a space of about 1/8" x 2.5" for oil to flow into the pump. at low rpms this works but as the rpms climb the pick-up that can,t get any oil to pump cavitates as it spins and fails to pump oil, result oil pressure drops untill rpms are lowered no matter how much oil is over the pick-up. simply checking to make sure that anout 1/2" of space is under the pick-up when the pan is installed cures that problem (a simple trick is to weld a 1/2" thick nut to the oil pump Pick-up base and test fitting the pan BEFORE WELDING THE PICK-UP TO THE PUMP BODY) what it comes down too in every case that Ive looked into so far is a improperly positioned pick-up or a non- baffled oil pan without a windage screen or less than 5 qts of oil in the system, not a problem of all available oil being pumped into the lifter gallery and valve covers like some people would like you to think. the MELLING COMPANY HAS THIS TO SAY Most of the stock automobile engines are designed to operate from idle to 4500 RPM. The original volume and pressure oil pump will work fine in this type of application. As the demands on the engine increase so does the demands on the oiling system and pump. The oil pump's most difficult task is to supply oil to the connecting rod bearing that is the farthest from the pump. To reach this bearing, the oil travels from three to four feet, turns numerous square corners thru small holes in the crankshaft to the rod bearing. The rod bearing doesn't help matters. It is traveling in a circle which means centrifugal force is pulling the oil out of the bearing. A 350 Chevy has a 3.4811 stroke and a 2.111 rod journal. The outer edge of the journal travels 17.5311 every revolution. At 1000 RPM, the outer edge is traveling at 16.6 MPH and 74.7 MPH at 4500 RPM. If we take this engine to 6500 the outer edge is up to 107.9 and at 8500 it is 141.1 MPH. Now imagine driving a car around a curve at those speeds and you can feel the centrifugal force. Now imagine doing it around a circle with a 5.581, diameter. The size of the gears or rotors determines the amount of oil a pump can move at any given RPM. Resistance to this movement creates the pressure. If a pump is not large enough to meet the demands of the engine, there will not be any pressure. Or if the demands of the engine are increased beyond the pumps capabilities there will be a loss of oil pressure. This is where high volume pumps come in; they take care of any increased demands of the engine. Increases in the engine's oil requirements come from higher RPM, being able to rev faster, increased bearing clearances, remote oil cooler and/or filter and any combination of these. Most high volume pumps also have a increase in pressure to help get the oil out to the bearings faster. That is what a high volume pump will do. Now let Is consider what it will not do. It will not replace a rebuild in a worn-out engine. It may increase pressure but the engine is still worn-out. It will not pump the oil pan dry. Both solid and hydraulic lifters have metering valves to limit flow of the oil to the top of the engine. If a pan is pumped dry, it is because the holes that drain oil back to the pan are plugged. If the high volume pump is also higher pressure, there will be a slight increase in flow to the top. let me point out this chart http://www.diabolicalperformance.com/clearances.html heres other info, http://www.babcox.com/editorial/ar/ar10180.htm http://www.thirskauto.net/BearingPics.html http://www.waynesgarage.com/docs/oil.htm http://www.jimcookperformance.com/TechNotes/TN%2023.html http://www.cryoeng.com/images/EngineDurabilitySecrets.htm http://www.melling.com/engoil.html http://members.aol.com/carleyware/library/engine2t.htm HERES more info on oil and filters HERE READ THESE http://www.babcox.com/editorial/us/uhs69720.htm http://www.co.broward.fl.us/aqi03202.htm http://www.motoroilbible.com/five.html http://www.motoroilbible.com/two.html http://www.motoroilbible.com/six.html http://www.exxon.com/exxon_lubes/tigerbytes/documents/brochures/bro0020.htm http://www.atis.net/oil_faq.html https://dallnd6.dal.mobil.com/GIS/MobilPDS.nsf/26 b7c4b33367a4a086256665004e4266/61638dff7d0453b085256b8400618b40?OpenDocument http://www.triumphspitfire.com/Oiltest.html http://www.fernblatt.com/longhurst/engineoil_bible.html http://minimopar.net/oilfilterstudy.html http://www.melling.com/engoil.html http://www.seansa4page.com/resource/synth.html http://www.geocities.com/MotorCity/Downs/3837/oilprime.html AND FOR THOSE OF YOU THAT DON,T WANT TO READ THROUGH THE LINKS THE SHORT ANSWER IS (1)MOST OILS AVAILABLE TODAY ARE VERY GOOD QUALITY AND FAR EXCEED WHAT WAS AVAILABLE EVEN TEN YEARS AGO. (2)CHANGING YOUR OIL AND FILTER OFTEN AND NEVER RUNNING LOW ON OIL IS THE KEY TO LONG ENGINE LIFE (3)SYNTHETIC OILS DO HAVE A SIGNIFICANT ADVANTAGE AS FAR AS HEAT RESISTANCE AND HIGH HEAT LUBRACATION (4) IF YOU DON,T ABUSE OR OVERHEAT YOUR ENGINE THERES LITTLE DISADVANTAGE TO USEING GOOD DINO BASE OIL UNDER 240 DEGREES OF ENGINE TEMP AS LONG AS YOU CHANGE OIL OFTEN (5)SYNTHETIC OIL DOES HAVE A BIG ADVANTAGE WHEN ENGINE OIL TEMPS EXCEED 260 DEGREES (F) oil info heres what consumer reports says about the better oils available http://www.unofficialbmw.com/all/misc/all_oilfaq.html All of the oils above meet current SG/CD ratings and all vehicle manufacture's warranty requirements in the proper viscosity. All are "good enough", but those with the better numbers are icing on the cake. The synthetics offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendency to form deposits, stable viscosity base, and low temperature flow characteristics. Synthetics are superior lubricants compared to traditional petroleum oils. You will have to decide if their high cost is justified in your application. I use puralator pure 1 filters or mobile 1 filters and mobile 1 synthetic oil 90%-95% and 10%-5% marvel mystery oil. ALL APPLICATIONS, read this, http://www.fernblatt.com/longhurst/engineoil_bible.html http://www.melling.com/engoil.html http://www.melling.com/highvol.html https://dallnd6.dal.mobil.com/GIS/MobilPDS.nsf/26b7c4b33367a4a086256665004e4266/61638dff7d0453b085256b8400618b40?OpenDocument http://www.shotimes.com/SHO3oilfilter.html

ok , your buddy wants to replace his 427 with a big blocks power but can,t afford the 502 and has approximately $4500-$5000 to work with as a budget, lets see what we can think up as a valid option heres a valid choice simply because this engine with a cam change gets close to 475hp http://www.sdpc2000.com/cart.asp?action=prod_detail&catid=120&pid=119 if your able to spend slightly more these options (below) may work as a starting point http://www.sdpc2000.com/cart.asp?action=prod_detail&catid=514&pid=623 http://www.strokermotor.com/535SB.htm if your really bucks down, heres a new 454 with efi for $3500 you can use a http://www.bgsoflex.com/megasquirt.html cpu and have a running EFI 454 for under that $4500 BUDGET http://www.sallee-chevrolet.com/sales.html NOW ill AGREE THAT IT WON,T HAVE THE SAME PERFORMANCE WITHOUT MODS BUT YOU WILL HAVE A RUNNING efi ,454 ENGINE WITH A ROLLER CAM, FOR UNDER $4500 AND MODS CAN BE DONE LATER

yes you can get an LT1 to make 500 flywheel hp N/A but it will not be very streetable, or cost effective to do it, mileage will not be good,and it will cost MORE than building equal power levels with a gen 1 350sbc. once you place the goal to get close to 500hp and above 500hp consistantly from an engine of only 350 cid,N/A , youve limited options, unless your willing to either spend fairly large amounts on forged parts, that can handle the high rpm stress like solid lifter roller cams, and machine work , porting or better heads and intakes,to allow the engine to breath effectively at higher rpms or a power adder like nitrous. or you reconsider and go with a stroker kit to increase displacement . most LT1-4 engines making a true repeatable 500 hp are either costing in the $6000 plus range or have larger displacement, or have power adders or a combo of those options simply because the stock engine is limited to about 1.2hp per cid without mods that quickly boost the price, displacement or use those power adders. 1.2 x 350=420 hp, one way or another those extra 80-100hp cost either lots of money or lots of time modifying stock parts now Im not saying it can,t be done, or done cheaply, but it is unlikely to be done without one of the listed options in my opinion your buddy should rebuild his bbc 427 and add nitrous and EFI, if done correctly he can get reasonably good mileage and make awesome power , yet still spend less than he would on the LT1 plus the mods and swap costs, a 427 bbc he already owns built and modified with the correct heads and cam,ETC. can easily produce better power than any 350/LT1 with the necessary mods plus the swap costs. the bbc has better flowing heads larger valves,angles valve heads larger displacement, much more potential more parts available stronger parts now that being said , read this http://www.phil.tobin.net/Hoover/top.html

GENERALLY THE DIFFERANCES WILL BE MORE THAN WEIGHT IRON HEADS..................................................ALUMINUM HEADS HEAVIER......................................................LIGHTER WEIGHT CHEAPER.............................................COST MORE VERY DIFFICULT TO REPAIR DAMAGE.....VERY EASY TO REPAIR DAMAGE CAN IN THEORY PRODUCE MORE HP.....................REQUIRE SLIGHT INCREASE IN CPR MORE PRONE TO DETONATE.............................LESS PRONE TO DETONATE CRACKS EASIER IF MISTREATED........................................WARPS EASIER IF MISTREATED MORE COROASION RESISTANT................................REQUIRES GOOD QUALITY COOLENT HARDER TO PORT....................................EASIER TO PORT EVERY GUY WILL SOONER OR LATER DROP A VALVE OR IN SOME OTHER WAY DAMAGE A CYLINDER HEAD IF YOUR RUNNING AN ENGINE CLOSE TO ITS PERFORMANCE LIMITS SOME OF THE TIME, YOU ONLY NEED TO THROW AWAY ONE SET OF DAMAGED HIGH DOLLAR PORTED IRON HEADS THAT IF THEY WERE ALUMINUM ,THAT COULD HAVE BEEN EASILY SAVED WITH WELDING TO REALIZE THE ALUMINUM HEADS HAVE A HUGE HIDDEN ADVANTAGE! sooner of latter every engine thats raced has problems that result in something coming loose and bounceing around in the cylinder, (VALVE FLOAT,BUSTED SPRING,CRACKED PISTON, DETONATION OR NITROUS DAMAGE CAUSEING A RING LAND TO CRACK,ETC> ) now that ALWAYS damages the cylinder head, in most cases ALUMINUM HEADS ARE EASILY REPAIRED and USUALLY FOR $300 or less IRON HEADS wind up in the dumpster behind the machine shop, now thats ESPECIALLY IMPORTANT if you just dumped big $$$ into port work! now as far as power goes I think the differance is very minor between aluminum and cast iron, and depends more on the port work and compression than the material used, I know I will only use aluminum heads on my personal engines, because I sure don,t want $1000 plus in heads and a weeks port work being thrown in the trash if I bust a piston or drop a valve someday!!! If you put too much heat on an aluminum cylinder head it will warp. If you put too much heat into an iron head it will crack. It's a lot easier to fix a warped aluminum head. A cracked iron head is usually trash. Just some food for thought The more important question is not iron vs aluminum but the air flow potential. Its really in youre wallet where you will notice the difference aluminum is easier to repair and weighs less, but heavy on the wallet. Iron is less on wallet but you could say disposable. as sooner or later problems occure with any heads personally if moneys tight ID GO GET THE TRICKFLOW 23 deg heads at $995

a few things you should know,if your thinking of swapping a LT1 intake to a L98 engine,look closely at the intake picture they are available NEW for $230 http://www.gzperformance.com/camaro.html (1) LT1 used REVERSE FLOW COOLING and NO DISTRIBUTOR (remember it used an OPTI-CRAP ignition,under the water pump) notice theres no place to install the thermostat or distributor!!!! as THE LT1 had that mounted to the water pump housing) (2)LT1 heads and intakes have the ports located about 1/8" higher in the location than L98 heads so gaskets don't line up correctly (THIS CAN CAUSE INTAKE PORTS TO LEAK) (3)mounting bolt angles changed , look at the center two bolt locations yes IT is possible to adapt to your engine, if your going to do it I STRONGLY SUGGEST STARTING WITH THE LT4 intake as it flows better http://www.hashmarks.com/techtips/intake_porting/intake_porting.htm http://www.popularhotrodding.com/tech/0803phr_beast/ if your not mechanically inclined this guy will do it for you http://www.lt1intake.com/ http://www.lt1intake.com/pricelist.htm but be aware that you'll lose low rpm torque, and unless you have installed a larger cam,better heads,headers, and changed rear gear ratios to move the engines average rpm operating range higher too match and significant ability to tune the new combo well after the intake swap is mandatory,the intake swap will be of little value as you will not gain much on the higher rpm end to offset that low rpm loss without those other changes CAN IT BE DONE? YES, IS IT A GOOD IDEA? THAT STRICTLY DEPENDS ON WHAT OTHER CHANGES YOU HAVE IN MIND TO MATCH THE SWAP. GENERALLY ITS not A good idea ON A stock L98 ENGINE, but has good potential on a serious engine, simply because its less restrictive to airflow PROVIDED the cam, heads and gearing also allows the engine to use that potential

you really should get these books and read them before going any further, it will help a good deal http://www.amazon.com/exec/obidos/ASIN/1557882169/qid=1075079777/sr=2-1/ref=sr_2_1/102-1234339-0571324 http://www.amazon.com/exec/obidos/tg/detail/-/0912656042/ref=pd_bxgy_img_2/102-1234339-0571324?v=glance&s=books http://www.amazon.com/exec/obidos/tg/detail/-/0895861755/ref=pd_bxgy_img_2/102-1234339-0571324?v=glance&s=books http://www.amazon.com/exec/obidos/tg/detail/-/1884089208/ref=pd_sim_books_1/102-1234339-0571324?v=glance&s=books http://www.amazon.com/exec/obidos/tg/detail/-/1557883572/ref=pd_sim_books_3/102-1234339-0571324?v=glance&s=books http://www.amazon.com/exec/obidos/tg/detail/-/0760302030/qid=1075080362/sr=1-2/ref=sr_1_2/102-1234339-0571324?v=glance&s=books

heres more bbc info, but don,t let the guys make you think only oval port heads work well! it totally depends on your combo,s rpm range,displacement,gearing,weight,cam timeing,etc http://www.idavette.net/hib/vette_bbfh.htm http://www.protopline.com/racingaluminumbbc.asp http://fteufert1.home.att.net/bbchevy/bbchevy.htm http://roadsters.com/bbc/#prep http://roadsters.com/bbc/#bore http://roadsters.com/bbc/#oval http://www.chevelles.com/racing/BBCombo.html http://www.edelbrock.com/automotive/raceheadbbchev.html http://www.dragraceresults.com/worldcastings/ http://www.nastyz28.com/bbcmenu.html general big block info! http://www.amotion.com/cbb.html http://www.edelbrock.com/automotive/headbbchev.html http://roadsters.com/bbc/ http://www.teufert.net/bbchevy/bbchevy.htm http://www.chevelles.com/racing/BBCombo.html http://www.racingengines.com/public/sales/wrldprd1.htm http://www.holley.com/HiOctn/ProdLine/Products/IEC/IECP/Chevy30.html http://www.mortec.com/location.htm http://home.hiwaay.net/~ppatter/patrick_budd_article.htm http://www.bigblockchevy.com/BittnerBoyz/460Alky1500Hp.html http://www.edelbrock.com/automotive/7161pp.html http://www.onlineperformanceparts.com/public/sales/ablock1.htm http://www.off-road.com/chevy/tech/454engine/ http://www.directhits.com/ChevyDynoReport.asp http://www.theengineshop.com/techinfo7.shtml http://www.dodgeram.org/tech/gas/specs/crank.html http://www.diabolicalperformance.com/diabolical540.html http://avs.epix.net/schorrperformance/cams/_ChevyBB_290+.htm http://avs.epix.net/schorrperformance/cams/_ChevyBB_290.htm http://www.diabolicalperformance.com/extremevalue468.html http://chevyhiperformance.com/techarticles/93650/ big blocks like more compression, bigger carbs and a slightly larger cam than small blocks if thats what your used to building btw

basically SCR (STATIC COMPRESSION RATIO is the max cylinder volume at BOTTOM DEAD CENTER COMPRESSED INTO THE VOLUME AT TOP DEAD CENTER ON THE ENGINE STROKE, WITH NO VALVE TIMING INVOLVED USE THIS http://www.newcovenant.com/speedcrafter/calculators/compressionratio.htm DCR (dynamic compression ratio) [/color]TAKES INTO ACCOUNT THE FACT THAT THE PISTON CAN NOT COMPRESS ANY CYLINDER VOLUME UNTILL ALL THE VALVES HAVE CLOSED DOWNLOAD AND USE THIS SOFTWARE http://cochise.uia.net/pkelley2/DynamicCR.html KEEP IN MIND YOUR ENGINE never sees static compression, it can only relate to dynamic compression, the only real use for SCR is a BASIS for finding the working engines DYNAMIC COMPRESSION RATIO LOOK heres a piston location rotational degree chart for a 350 with 5.7" rods http://www.iskycams.com/ART/techinfo/ncrank1.pdf HERES A CAM SPEC CARD http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=119661&B1=Display+Card if the static compression is 11:1 the engine will see close to 7.8:1 with that cam

HERE TWO CHECK LISTS heres a few things that should always be checked on an engine build heads are the pushrods perfectly strait? do the pushrods flow oil? rocker studs/guides torqued correctly? do the head bolts have washers under the bolt heads? are they the correct length for the cylinder heads in use? have the heads been pocket ported? combustion chambers unshrouded? intake ports gasket matched" are the valve guides cut to the correct length? are the heads pocket ported? is the retainer to valve guide clearance correct? are the valve guide oil seals installed? is there valve spring seats installed? inner damper springs installed? spring bind height checked? (to exceed max valve lift by .050 min.) oil return holes cleaned of casting flash? were steam holes in heads necessary? were the spark plug threads of a installed spark plug extending into the combustion chamber? rocker slot to rocker stud clearances ? retainer to valve guide clearances? spring bind height checked for the correct spring pressure? valve lash/preload ? are the valve springs the correct tension,height?dia. keeper the correct angle? style? size? valve seats the correct angles? valves back cut? valves the correct length, stemsthe correct diam. strait? rockers the correct ratio? were the valve to valve guide clearances checked? were the heads milled? did the head gasket overlap the bore? what are your valve train clearances? is the rocker arm geometry correct! chambers CC,ed port work..(some steps optional) (1) open throat to 85%-90% of valve size (2)cut a 4 angle seat with 45 degree angle .065-.075 wide where the valve seats and about .100 at 60 degrees below and a .030 wide 30 degree cut above and a 20 degree cut above that rolled and blended into the combustion chamber (3)blend the spark plug boss slightly and lay back the combustion chamber walls near the valves (4)narrow but dont shorten the valve guide (5) open and straiten and blend the upper two port corner edges along the port roof (6) gasket match to/with intake and raise the port roof slightly (7) back cut valves at 30 degrees (8) polish valve face and round outer edges slightly (9)polish combustion chamber surface and blend edges slightly (10) remove and smooth away all casting flash , keep the floor of the port slightly rough but the roof and walls smoothed but not polished. (11) use a head gasket to see the max you can open the combustion chamber walls (12) blend but don,t grind away the short side radias block is the oil pump pick-up mounted 3/8"-1/2" from the oil pan floor/ is the windage screen mounted about 1/8" from the rotateing assembly/ is the pick-up brazed to the pump body? has the oil pump relief piston in the oil pump been checked for free ,easy movement? clearance? spring tension? is the oil pump pick-up tube inserted too far into the oil pump body,(binding the gears) has the block been clearanced for the rotating assembly? has the block been aline honed? is the crank strait? are the damper install keyway and threads ok? counter weights clearanced? MAGNAFLUXED? OIL PASSAGES CLEANED? GALLERY PLUGS INSTALLED CORRECTLY? has the cam to rod bolt clearance been checked? piston to valve clearances checked? piston to bore clearances? TRUST BEARING CLEARANCE? what were the piston ring to slot clearances? RING GAPS? were the rings all checked individually for end gap in the cylinders they were used/installed in? were the rings checked to make sure the correct side faced up, and the correct ring was in each groove? what were the back clearance on the rings? were the oil ring expanders carefully fitted for correct drag? were the oil ring scraper ring rails checked for end gap? total cam lift and remaining clearanceS? WAS THE CAM DEGREED IN? main bearing clearances? what is the main bearing run-out clearance piston to head clearance? (QUENCH?) head gasket to coolent holes checked? magnets installed? rod bolt to block clearances? what tq reading is necessay to spin the crank with no rods attached? are the rod bolts and main caps torqued correctly? (rod bolts checked with a bolt stretch gauge?) did you check the block for a strait main cap alignment? what size journals and what were the bearings edge to filet clearance?? are the journals checked for finish and run-out/tapper? did you use moly lube to assemble? correct bearing crush? did you pre-lube before start-up? did the distributor gear fit the cam gear precisely? was the distributor oil flow mod done? was the correct style distributor gear used? did you check the piston to piston pin bores for fit and clearance? did the piston pins to snap ring clearance seem overly tight? if they are pressed pins were they correctly matched and checked for free movement in the pistons? was the engine ballanced? cam button installed?, and lock plate installed? were the rods resized? checked for parrallel bores/were the rods strait? piston valve clearance notchs correctly located on the pistons? edges smoothed? were the rods checked for length? is there a few thousands clearance on the oil pump drive shaft AFTER the distributors bolted down? did you install a steel collar on the oil pump drive shaft? was the rod to piston pin side clearance checked? (at 4 places seperated bye 90 degree spots) does the oil pump drive shaft mid section clear the block with the pump installed? whats the starter to flywheel gear clearance? is the pilot bearing to trans imput shaft clearance ok? is the front motor mount bolt to fuel pump pushrod clearance ok? did the fuel pump pushrod move easily/ are you possitive the pistons were installed with the correct valve relief in the correct location?(eiieeiie) were the pistons installed with the correct side facing forward/ what torque values were used on all fasteners/ were they the correct length and type bolts? were the bores honed with a torque plate in place? was the cylinder finish correct for the type rings used? was the oil pump itself checked for free spin and clearance AFTER THE PICK-UP WAS INSTALLED? was the cam drive checked for free rotation and drag/ were the oil passage plugs drilled for extra oil flow? were the lifter bores checked? cam to timing cover clearance? cam journal to cam bearing clearances? was the cam journal run-out checked? was the cam degreed in or just lined up useing factiory index marks? has the rod and windage screen to oilpan clearnce been checked? does the dipstick & tube clear the windage screen? was the cam lobes/LSA/LIFT CHECKED? is the deck square/level? whats the cross hatch hone angle? what grit hone was used? are all the threads clean/clear? brass freeze plugs installed? block painted? go through your standard check list, for carb cars,(some of the info works on all cars) check that theres spark at all the plugs and the plugs are burning cleanly check that your getting the correct voltage at the coil/ignition and plugs are not loose and gapped correctly, check that the wires and coil are not arcing or shorting out check that the throttle linkage opens fully look for coolent on the plugs or coolent leaks under the car look for loose vacume hoses, crimped lines, ETC, check your oil level is correct do a compression test if anything looks bad on the plugs or engines seems to not be running on all 8 cylinders look for rocker arms that are not moveing correctly,bent push rods, loose rocker arm studs, broken valve retainers, or valve springs check that your getting good oil pressure at idle(pressure switch can turn off ignition) check that cam and ignition timeing is ok/not changed (timeing light, loose timeing chain on cam drive, check that the distributor has not moved, check with a timing light)check that the rotors not loose under the distrib. cap and the distrib. cap itself is not loose or cracked check that you have not wiped a cam lobe, broken a valve spring or valve spring damper. look for loose rocker arm adjustment look for vacuum leaks look for loose electrical connections, fan belts or accesories that might be having a bearing or electrical failure putting excessive drag on the engine look for low fuel pressure/clogged fuel filter, bad fuel, water in gas, rust in the gas or just low on fuel. look for plugged up air filter/bad pvc/egr check catalitic converters not plugged/restricting the exhaust flow check for moisture in distributor cap. check that the damper on the crank has not come loose and moved the timeing marks on the outer ring by having the elastic break loose between the rings on a stock style damper or that the key in the crank has not sheared allowing the damper to move possition do a CYLINDER LEAK DOWN test make sure the fuel pressure is correct and the fuel supply system is working at 6psi-8psi before the pressure regulator and about 5psi-6psi at the carb http://www.centuryperformance.com/timing.htm http://www.centuryperformance.com/vacuum.htm http://www.boyleworks.com/ta400/psp/distcurve.html (pontiac but info the same for chevy) http://www.73-87.com/garage/101s.htm http://www.73-87.com/garage/hei.htm [image]http://www.73-87.com/garage_photos/disremov/firingorder.jpg[/image] [image]http://www.centuryperformance.com/images/tech/fuel2.gif[/image] look for spark plug wires that are loose or not correctly connected heres info later efi engines like my corvette can use HERE TAKE IT STEP BY STEP http://www.c4vettes.com/maf.htm http://www.c4vettes.com/l98.htm http://www.midniteworks.com/vettecodes/vettecodes.html L-98 Engine Start Sequence When you start an L-98 engine Corvette, a series of events take place that causes the engine to run. Knowing the sequence will help you troubleshoot no start conditions. Fuel Rail Pressurization: When you first turn the key to the “on†position, the fuel pump will run for 2 seconds pressurizing the fuel rails. There is a Shraeder valve on the passenger side fuel rail near the rear of the engine and if you measure the pressure there after the pump runs, you should see between 40-42 pounds of pressure. The reading will go to 38-40 pounds nominal once the engine is running. Initial Crank Action: If you then rotate the key to the start position (assuming the anti-theft system has not disabled the starter), the engine will rotate. Once the oil pressure has reached 4 PSI, the oil pressure switch will close allowing the fuel pump to run. (Note that you should have a black oil pressure switch/sender. It is mounted behind the distributor on the driver’s side and if it is not black, it is suspect due to a run of bad units that stayed in the GM parts pipeline for some time). The distributor will send a string of pulses to the ECM (Engine Control Module) in response to the engine being rotated by the starter. These pulses continue as long as the engine turns (both starting and running) and if they are not present, the engine will not run. ECM Reaction: If the ECM sees oil pressure greater than 4 PSI and the reference pulses from the distributor, it will energize the injector drivers which will begin pulsing the injectors on for 4 ms (milliseconds) periods. (In the L98, all injectors on one side of the engine fire at the same time followed by all injectors on the other side firing at the same time. On the LT-1, the injectors are fired individually at the appropriate time). The ECM will also pull in the fuel pump relay in effect paralleling it electrically with the oil pressure switch. (If the fuel pump relay fails, you can still normally get the car to start and run unless you can’t make at least 4 PSI oil pressure. This is a “limp home mode†feature put in place to allow for a fuel pump relay failure). The ECM also monitors the TPS (Throttle Position Sensor mounted on the throttle body assembly) and wants to see .54 volts at this time. If it sees appreciably more than 0.54 volts, it will assume the engine is flooded and the driver has pressed the accelerator to the floor to clear the flooded condition and restrict the fuel flow as a result. (.54 volts during start and at idle from the TPS is very important to both starting and run performance.) Assuming the ignition module is good (meaning there is a spark of sufficient intensity to ignite the fuel), the engine will “catchâ€. Engine "Catches": When the engine catches, the MAF (Mass Air Flow sensor mounted just ahead of the throttle body) sends a signal to the ECM advising that air is flowing and also just how much air is being pulled through to the intake manifold. The ECM takes note of the amount of air being consumed and adjusts the injector pulse width to around 2.2 ms nominally so as to attain a proper air/fuel mixture to insure combustion. (This is how the 1985 through 1989 L-98 works. For information on the 1990 and 1991 L-98 variant, see the Note below). The engine should show an initial idle speed of around 900-1100 RPM and then slowly diminish to 600-700 RPM unless the air conditioner is on in which case it will run at around 800 RPM. If this does not happen, the Idle Air Mixture valve (located on the throttle body) may be misadjusted. Alternatively, there may be a leak in the intake manifold or another vacuum leak may be present. Listen for hissing sounds---there should be none. ECM Mode: The engine will now be in Open Loop mode meaning that the ECM is controlling the air/fuel mixture by referencing values stored in memory. Once the Oxygen sensor (mounted on the exhaust pipe) reaches operating temperature of several hundred degrees, the Manifold Air Temperature (MAT) sensor shows an intake air temperature of more than 140 degrees and the Engine Coolant Temperature (ECT) has reached 160 degrees, the computer will switch to closed loop mode meaning the Oxygen sensor’s output is examined along with the MAT and ECT outputs and the ECM adjusts the injector pulse widths (more “on time†or less “on timeâ€) to constantly strive for a 14.7:1 air/fuel mixture which is the best mixture to hold down pollution. Note that prolonged idling can force the computer back into open loop mode. Note: In 1990, the MAF was eliminated from the engine in favor of a speed/density system. This system uses a sensor called the MAP sensor which measures the Manifold Absolute Pressure (hence the name MAP) and compares it with the atmospheric pressure outside the intake manifold. This information, coupled with the Manifold Air Temperature, Engine Coolant Temperature and Engine RPM is used by the ECM to determine the amount of air entering the cylinders. It is a different way of reaching the desired 14.7:1 air-fuel mixture ratio but functionally is like the MAF system in that the ECM uses the feedback to control the "on time" for the injectors. Corvette used this approach in the 1990 and 1991 L-98 engines and in the 1992 and 1993 LT-1 engines. With the 1994 model C4, they went back to the MAF system. Note that MAF based systems are far more accurate since they measure air flow directly whereas the MAP system infers air flow indirectly. A multitude of things can throw the calculation off and Corvette returned to the MAF system beginning with the 1994 C4 (with a MAP backup). From a troubleshooting standpoint, the MAP operation comes into the sequence the same place that the MAF does. Summary: If you have a no start condition or if the L-98 starts and then dies, check the above items in sequence to see if all the events are occurring as required. A Scan Tool makes this job much easier and is a highly recommended troubleshooting aid for these sorts of problems. Most of the C4 Corvettes used a MAF (Mass Air Flow) sensor to determine how much air is being pulled into the intake manifold. The exceptions are the 1984 Corvette that used a speed density system--a sort of predictive method of measurement---and the 1990 through 1993 C4 models which were also speed density based. In 1994, Corvette went back to the MAF based system but used the speed density approach as a back up. (1989 Bosch MAF installation shown at right). A Mass Air Flow sensor has an extremely fine wire inside its bore. The 1985 through 1989 C4 engines used a Bosch MAF sensor that heated the wire to 100 C. The 1994 and later C4 models used a AC/Delco MAF that heated the wire to 200 C. The amount of current required to reach the temperature is measured in each case. (Note: the LT-5 engine used in the ZR-1 used a speed density system and continued to use that system in 1994 and 1995 since the engines had already been made prior to the last two years of production. The ZR-1 therefore has no MAF even after Corvette went back to the MAF based system). Theory of Operation As the air travels past the heated wire enroute to the intake manifold, it will cool the wire and additional current is added to again heat the wire to the design temperature. Since the amount of air moving past the sensor is directly related to the amount of cooling experienced by the heated wire, a feedback condition is established whereby the exact amount of moving air is directly related to the amount of current passing through the wire and the intake air is therefore precisely measured. Once the amount of air is known, the computer controlling the engine can add or subtract fuel as required to maintain the magic 14.7:1 air-fuel mixture resulting in the cleanest burn possible from an emissions (pollution) standpoint. It does this by varying the "on time" of the fuel injectors. The injectors are pulsed on and off and the width of the pulse is lengthened or shortened as required. When you first start a typical engine, the pulse width is around 4 milliseconds but as soon as the engine "catches" the pulse width is shortened to about 2.2 milliseconds for idle. During operation, the measured air flow through the MAF will cause the computer to increase or decrease the pulse width as explained above. MAF Operating Conditions The Bosch MAF is more complex than the AC/Delco version. Both measure the air flow but the Bosch MAF has a circuit called the 'burn-off circuit' that cycles on for about 2 seconds when you shut the engine down. This circuit heats the wire to a high enough temperature to burn off any residue that may have collected on the wire during operation. If you are in a quiet area, you can hear the relays click on and then off on a 1985-1989 C4 as the burn-off cycle occurs. There are two relays involved with the Bosch MAF: A power relay that passes current to the MAF wire during normal operation and the burn-off relay that provides the current for the cleaning cycle. Both are located on the firewall in the engine compartment, just behind the battery on the drivers side. Bad MAF power and burn-off relays can cause hard starting problems and should be changed periodically as preventative measure and any time you experience hard starting conditions. The AC/Delco MAF has a power relay but no burn-off relay. For this reason, you should pay even closer attention to the condition of your air filter on a later model C4 than normal since a contaminated wire in a AC/Delco MAF is going to stay contaminated for the most part and cause false signals to be passed to the computer. Also, the Bosch MAF outputs its information as a analog signal to the computer but the AC/Delco sends its signal as a digital component of varying frequency. For this reason, you cannot measure it's operation directly. A scan tool is generally the best way to troubleshoot engine problems and with the 1994 and later Corvette, it is virtually mandatory. (An oscilloscope will also work on the AC/Delco MAF but a regular test meter will not). MAF Problems Faulty MAF sensors will normally light the check engine light on the drivers information center if the problem is constant and store a trouble code. If intermittent, a trouble code will still be stored as long as the battery is not disconnected. Normally, the problem is a poor connection at the sensor and wiggling the wires, unplugging and reinserting the connector will often cure the problem. A faulty MAF will normally cause a no start or difficult start condition and although you can eventually get the car into the "limp-home" mode in most cases, you need to attend to the problem ASAP. AC/Delco sensors can become intermittent or give false readings if the wires become contaminated as explained above. The MAF is a critical part of the emission control system and as such will cause the computer to react to problems very quickly, setting trouble codes and reducing performance in ways that cannot be ignored for long. MAF Mods The Bosch MAF is often modified by removing the two screens that are present in the front and rear of the cylinder. Removing these screens significantly increases the air flow through them and this results in more horsepower. Removing the screens is an old trick from the Corvette Challenge days in 1988 and 1989. It does work but is illegal in many states so be advised not to do anything that will get you arrested for a pollution violation. The AC/Delco MAF is not readily modified. It is what it is but since it is a larger diameter than the Bosch, it responds well to changing the air filter to a free flowing type such as the K&N filter. Welcome to C4 vette codes it is very ....repeat very important that if you are not savvy of working on your vette ...you would be better off - taking your car to a dealership for repairs on your trouble codes. However if you feel that you want to dive right in ..than you have come to the right place.First locate your car's alcl this component is located just below the instrument panel and to the left of the center console. Remove the plastic cover the first two slots to your right are the A & B slots for a drawing of the alcl module's picture is added below. The A slot is the diagnostic slot and the B slot is the ground slot. insert the computer key into these slots (with the engine off) this is very important...now only put the ignition key to on ( not start !!!) the check engine light will display a code 12 which is one flash followed by two flashes. this code will be flashed three times ..followed by the trouble code stored in your car's computer. what ever the code is it will be flashed three times. have a paper and pencil ready and write down the code . code 13 =1 flash followed by 3 flashes =>oxygen sensor code 14 =1 flash followed by 4 flashes =>coolant sensor code 15 =1 flash followed by 5 flashes =>coolant sensor code 21 = 2 flashes followed by 1 flash =>throttle position sensor code 22 = 2 flashes followed by 2 flashes=> throttle position sensor code 23 = 2 flashes followed by 3 flashes=> manifold air temp sensor code 24 = 2 flashes followed by 4 flashes=> vehicle speed sensor code 25 = 2 flashes followed by 5 flashes=> manifold air temp sensor code 32 =>egr system code 33 =>map sensor code 34 =>maf sensor code 35 => idle air control code 41 => cylinder select error code 42 => electronic spark control code 43 => electronic spark control code 44 => lean exhaust code 45 => rich exhaust code 51 => PROM code 52 => fuel calpak code 53 => system over voltage code 54 => fuel pump circuit code 55 => ecm code 62 => oil temp please remember that if you have the computer key installed in the alcl and you start the engine ( you will ruin the engine's computer ) only put the ignition to on (not to start) If you should get a check engine soon display.. you can use the above procedure and codes to buy the right part or at the very least to keep from getting taken for a ride and be made to pay hight prices for some inexpensive module that you could have installed yourself. You never ask a barber if you need a haircut .. so you have to be on guard they will see you comming a mile away. If your engine displays a trouble code ... your engine will go into limp mode ..it will still run but very poorly. you might be able to reset the computer if it will not start ( just to get home ) by disconnecting both battery cables and re-installing them ...this is not recommended ..but if you are stranded it might help unitl you get your car home or to a repair shop..good luck

Nic-Rebel450CA read these first http://www.oregoncamshaft.com/cam-basics.html http://www.chevytalk.com/tech/101/Cam_Theory.html http://www.newcovenant.com/speedcrafter/tech/camshaft/1.htm I would HIGHLY recommend that YOU DO NOT USE THAT COMPANYs services I know several people who have that reported less than satisfactory results if you don,t want to pick your own cam to match your combo the information is readily available for FREE if your willing to follow these instructions below EXACTLY (1) determine exactly what your true engine combo, static compression,parts list, vehical weight,rear gear ratio, tire height,,trans stall speed , ETC.acctually is, decide on what type of cam you want and can afford,( flat tappet or roller whether its to be /solid/hydrolic,) write it down so you can read it to them word for word, exactly the same info, do not purchase a cam untill all the data from all the companys is averaged (2) call a minimum of FIVE cam companys TECH help lines and give EXACTLY the same info to each,(REPEAT..give EXACTLY the same info to each, write down the suggested cams LSA.LIFT, durration @.050 (3) average the results and buy the cam that matches that result the best, if you must choose a cam that matches the AVERAGE thats not an exact match , choose the cam that is the closest to that average but has a WIDER LSA and LOWER duration (4) this method will keep you from taking bad advice and get you a good combo I would highly suggest these cam companys CRANE 1-386-258-6174 Tech Line CROWER 1-619-661-6477 LUNATI 1-901-365-0950 ISKY 1-323-770-0930 ERSON 1-775.882.1622 engle cams 1-(310) 450-0806 PS theres a well known cam company thats NOT listed that has CONSTANTLY given me BAD advise, THATS WHY THEY ARE NOT LISTED! NO IM NOT GOING TO NAME THEM

judging from that reponce it would seem your interested in building a an LS1 (Z) theres little doubt that a properly modifyed LS1 with turbos will make a killer combo a combo that will provide spectacular performance, while Im reasonably sure I could build more power for similar money with the older GEN1 engine I doubt the ENGINE weight could be lowered to similar levels since the LS1 has an advantage as to total weight and already has the aluminum block AFR has 225cc heads that when matched to a good INTERCOOLED turbo combo should easily get you what your looking for 225cc LS1 Mongoose Strip Head The Ultimate Bolt-On Emission Legal Street/Strip Weapon For the maximum street/strip LS1/LS6 aluminum cylinder head AFR’s all new 225cc emission legal head are hands down the best choice. Specifically designed for 1995 to present Gen-3 Chevy Corvettes, Camaros, and trucks. AFR’s LS1 head offers unmatched flow performance and features 2.080 intake and 1.600 exhaust valves with AFR’s iron ductile interlocking valve seats. The 225cc is ideal for normally aspirated 396C.I. to 427C.I. It is available with 66cc and 76cc combustion chambers. An affordable “as cast†version is also available. AFR’s LS1 is a direct bolt on, no special parts required. Structural features like Air Flow Research’s trademark 3/4†thick head deck, a must for blown and nitrous applications, reinforced rocker stud bosses and thick wall runners provide unparalled durability. An exclusive new modern combination chamber design with double quench pad area helps the LS1 generate huge low and mid lift airflow numbers. If you need a snake charmer for that pesky neighborhood “Cobra Mustang†look no further! Note: Hydraulic roller cams typically experience valve float at 6000-6200 RPM because of their fast ramp rates. AFR suggest you upgrade your springs to AFR part #8019, 1.450 O.D. double with dampener valve spring with higher pressures to reduce the chances of valve float at higher RPM’s. -------------------------------------------------------------------------------- 225cc Mongoose LS1 Racing Head Part Numbers CNC Ported Pairs of Cylinder Heads Complete With Parts and Ready to Install CNC Street Porting Description Part Number 225cc CNC Ported w/parts 66cc 1610 225cc CNC Ported w/o parts 66cc 1620 225cc CNC Ported w/parts 76cc 1630 225cc CNC Ported w/o parts 76cc 1640 220cc As Cast w/ parts 64cc 1650 220cc As Cast w/o parts 64cc 1660 220cc As Cast w/ parts 74cc 1670 220cc As Cast w/o parts 74cc 1680 220cc As Cast w/ parts 66cc CNC Chambers 1650-1 220cc As Cast w/o parts 66cc CNC Chambers 1660-1 220cc As Cast w/o parts 76cc CNC Chambers 1670-1 220cc As Cast w/o parts 76cc CNC Chambers 1680-1 http://www.tradezone.com/vette/engine.html

while all options have thier weak points I think youll find that the gen 1 sbc engine has significantly greater choices on parts and at significantly lower prices as an example the main problem youll have is finding great large port heads and super strong blocks and rotating assembly parts all are very easy to obtain for a GEN1 and YOULL TEND TO GET BETTER PARTS PER DOLLAR SPENT, if you have a thick wallet, gen,two has not nearly the parts selection and I don,t think its going to get better, the LS1 is a good but expensive choice look this over AND THIS http://www.montygwilliams.com/ thought on the intake manifold design as it pertains to turboing (Stealth, LT1, LS1) would also be appreciated... since your intending on a pressurized intake Id look into a highly ported modified single plane intake like the STEALTH RAM if MAX FLOW is the MAIN CONCERN AS THE DIRECT SHOT INTO THE HEADS WILL HELP THE POWER POTENTIAL or if max flow and HOOD CLEARANCE ARE BOTH MANDATORY,a EDELBROCK SUPER VIC CONVERTED TO EFI or the IF YOU HAVE THE HOOD CLEARANCE http://www.holley.com/HiOctn/ProdLine/Products/AMS/AMSM/7540P.html http://www.holley.com/HiOctn/ProdLine/Products/AMS/AMSM/f9901-101-1.html http://www.holley.com/HiOctn/ProdLine/Products/AMS/AMSM/300-110.html

"Do you think it would be a worthwhile investment to buy the MSD 6AL kit from Summit (with Blaster 2 coil and all that for stock HEI ignition) right now? 250 bucks" the MSD 6AL kit works very well,it tends to make the engine run smoother (especially between 450rpm-6500rpm and at idle) and pass emmissions easier, but dont look for a noticable change in hp unless your engines current ignition is faulty, would I advise buying it? well I would, but then I already run an MSD that Im very happy with on my corvette, so Im slightly bias toword that ignition system yet let me repeat, the ignition is not going to produce a noticable power increase. but it is likely to help maintain what you do build