grumpyvette

lengthening the collector and tapering the exit to a smaller dia tends to lower torque peak rpm and widen the torque curve, both help mid range pulling power, your 1 7/8" primairies are too large in dia. for the ideal power range at that gearing and compression ratio,and this will help http://auto.howstuffworks.com/question172.htm http://www.burnsstainless.com/TechArticles/Theory/theory.html http://www.thedirtforum.com/headercalc.htm http://www.rbracing-rsr.com/runnertorquecalc.html http://succ.shirazu.ac.ir/~motor/page7f.htm http://pweb.jps.net/~snowbum/InExTuning.htm http://www.spectrum5racing.com/Technical/s5headerRevA.pdf if your really serious, addinging something like this adds mid rpm range power also welding these to the end helps also, as it noticably increases the scavaging once the exact length required is tested and found

http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=23421 its a waste of time to build checking pushrods when thier dirt cheap to buy

the main restriction is the hydrolic lifter cam the durration and type of cam is not nearly correct, for a serious motor,your compression ratio should be slightly over 10:1 depending on the head gasket your useing and deck height, so swap to on of these cams, (below) and the thinnest head gasket you can get that maintains a .040-.044 quench distance (yes check ALL your clearances) http://www.crower.com/misc/cam_spec/cam_finder.php?part_num=00322&x=34&y=8 http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=114681&lvl=2&prt=5 ID also do the following mods Id install a tapered collector extension that slowly reduced & extended the collector exit dia. and added a minimum of 12 inches to the current collector length http://www.holley.com/11752HKR.asp ID swap to caltrac bars http://www.hotrodsandhemis.com/Traction.html and install a 4.11 rear gear ratio the CALTRAC BARS and the cam SWAP are basically mandatory, the rear gear ratio and header collectors help but are less important btw this may help http://www.ramairbox.com/kits.html and this http://www.professional-products.com/manifoldsProductSBchevy.php (#52031) those mods will get you much closer to the very low 12 second range, adding this also will get you into the 11s http://store.summitracing.com/partdetail.asp?autofilter=1&part=NOS%2D02001NOS&N=400047+115&autoview=sku

sure! as the engine rpms increase the velocity and frequency of the piston strokes increases and the time between those strokes decreases example at 1000rpm theres 500 intake strokes per minute or 8.3 intake strokes per second, at 7000rpm,youll naturally have only 1/7th the time, the pistons moving 7 times faster so you get 58 intake strokes per second, now up to about 3000-4500rpm (depends on factors like port size, compression ration,etc.)the ignition timing needs to advance to allow time for the cylinders to build the necessary pressure curve, but above that rpm range the combination of the fuel/air mixs vastly faster movement in the cylinder, turbulance in the cylinder and heat in the chamber increase the burn rate, and the higher the rpms the faster this becomes (within limits) so more advance in the ignition becomes counter productive. now remember its the TIME it takes from ignition to get the pressure built, not the degrees in advance of TDC, its the peak power that we are attempting maximize by trying to regulate the burn so that the pressure curve over the piston does the maximum work and the power will be lower if the piston must try and compress a mix where the pressure resists the pistons upward movement against it. now at some point, lets say, an example of ,(6000rpm) the burn with the ignition fully advanced is going to produce a good amount of pressure BEFORE TDC as the pistons still in its upward movement, that will tend to work against your total power output, simply because a good deal of potential power is wasted compressing a mix thats been ignited and burning fast enought that youll be wasteing a good deal of that pressure curve. retarding the timing moves the pressure curve at this rpm range back to the past TDC where it does you some good.

notice the tq peaks well below the horsepower peak and the house power peaks in the 6000rpm-6500rpm band, peaks but does not fall off quickly untill your at or above 6700rpm, a combo like this (ESPECIALLY WITH GOOD HEADS AND A LOW RESTRICTION EXHAUST) with tuned headers produces street tire destroying power from just over 3000rpm to well over 6000rpm, in a 3000lb or lighter (Z) that will easily get your car into the low 12s/high 11s on street tires if its set up correctly. http://www.gordon-glasgow.org/hpcalc.html http://vette.ohioracing.com/hp.html http://www.escort-us.com/1-4ET.htm http://www.runeb.org/www_docs/Jexoticasite/frames/horsepowercalc.htm

why change your ignition advance curve, on a high performance engine? Ill over simplify it for you, as the load rate on the engine increases the rate of accelleration of the piston away from TDC tends to slow as does the rate of increase in the number of strokes per second, cylinder pressures build rapidly from the time the spark ignites the compressed mix untill peak pressures are reached,but not nearly instantly, it takes TIME for usefull pressure to build up, as the pressure in the cylinders before or at TDC does nothing to produce power ,in fact it tends to work against the engines efficiency, but because theres a lag between ignition and the useable pressure over the piston you need to advance the timing, so that the majority of that pressure peaks slightly after TDC and maintains that positive pressure over the piston for as long as possiable, that pressure curve and the necessary required ignition advance required to get it varies with the resistance or LOAD the engines working against and the RATE at which the piston moves away from the TDC point. if that load slows the piston to much it gives the cylinder a chance for secondary ignition(detonation) to occure, as the pressure and time both have an effect. you can get away with a faster advance if the piston moves rapidly away from TDC,IE ligher loads or a higher gear ratio that allows the engine to build rpms faster, factors like, octane used,air temps in the cylinder,quench ,and valve timing, even the rod length/to stroke ratio, effect results here things to read http://hcs.harvard.edu/~jus/0303/kuo.pdf http://superchevy.com/technical/engines_drivetrain/accessories_electronics/0411sc_crane/ http://www.erc.wisc.edu/modeling/multi_dimensional/ModelingMtng2004/7-NSMBpaper.pdf look here http://www.iskycams.com/ART/techinfo/ncrank1.pdf now compare your cam choices and notice that the valves open to bleed off pressure and the valves close to maintain pressure while the piston is a good deal closer to TDC tham most people realize, most of the effective pressure occures in the upper 1/2 of the stroke, with very little useful pressure in the cylinder after 90 degrees past TDC heres a cam I use alot http://www.cranecams.com/?show=browsePar...lvl=2&prt=5 notice when the exhaust valve opens, and compare that to the location of the piston in relation to the peak cylinder pressures as they relate to the pressure curve over the piston, youll quickly notice that the peak pressure occures between tdc and at most 30 degrees past TDC and has dropped off drastically by the time the exhaust valve opens

I had a 1996 full size 4x4 bronco untill recently (it was totalled when a large truck hit me), with 240,000 miles on it and the valve covers had never been off it, it was the shop parts chaser and my ELK, hunting ride,it was completely dependable. I purchased it based on results my hunting partner got! (he had over 400,0000 miles on the original engine and trans) with only the normal, water pump,brakes,belts,hoses , bulbs,etc. needing replacement,but then I maintain my cars/trucks constantly,(like he does) with, all fluids, lube,filter and oil changes and frequent tune ups and tire ballances,shock and brake replacements ETC.,almost on an insane /repeat basis because I hate getting stranded. if its a full size bronco thats been well maintained it should be a good transportation truck but get lousy mileage, the best IVE seen was in the 12-15mpg range, the smaller bronco IIs were and are in my opinion garbage! I don,t know ANYONE whose purchased one that was really happy with it!

"Am I wrong in assuming that a 383/396 is only good for stump pulling torque?" yeah, your wrong, here! the cam,compression,and heads have a good deal more to do with the way the engine responds, stroke alone is basically not a big factor,think about it, a 427 big block engines known as a high rpm screamer, it has a 3.76 stroke just like a 383,your 305 had a short stroke,(3.48" just like the 350, but it was not a high rpm combo! yet a 3.48" stroke in a 350 can be! build the engine as listed with the cam and compression listed, ETC. and youll see a totally differant style engine that wraps up quickly to 6700rpm, with a torque curve that starts off low and goes up rapidly maybe one of the guys here can post a dd-2000 dyno curve to show you

ok ,first Ill point out that its silly to build any combo smaller than a 383-396 simply because the costs involved are just not that much greater and the potential performance IS significantly higher. next I think your missing the OPTION of useing a flat tappet solid lifter cam, it will approach the rollers power, rev far higher than a hydrolic flat tappet and be far less expensive than a roller cam. next you failed to list the heads youll use, but Id assume they are similar to the early performance cast heads, (im forced to point out they have less potential than the better aftermarket heads) but lets assume youll use them, youll NEED a FORGED AND BALLANCED ROTATING ASSEMBLY TO USE SERIOUS NITROUS http://www.flatlanderracing.com/index.html heres a basic combo your fuelie or similar heads (clearanced for a .550 minimum lift) a rotateing assembly to build a 10.7-10-9:1 cpr 383-or-396 sbc add a crane 110921 cam, or if your willing to sacrifice a few peak hp for a noticably smoother but still lopey idle a #114681 cam http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=110921&lvl=2&prt=5 or http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=114681&lvl=2&prt=5 add a professional products #52030 intake http://www.professional-products.com/manifoldsProductSBchevy.php a good 7-8 qt baffled oil pan with matching z28 pump and pick-up similar to this http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=21571 a good 750 cfm carb results will be a well balanced combo that has both excellent tq and power in the 3000rpm-6700rpm range http://www.bracketmasters.com/small_block_stroker_383_cu.htm

http://www.passandseymour.com/pdf/U077.pdf http://www.passandseymour.com/pdf/U013-U020.pdf http://www.sigmasystems.com/Techdoc/Tech_Docs/SigmaPowerPlugs.htm http://leviton.com/pdfs/d-503/d-503T.pdf (see page 21) http://www.danielwoodhead.com/pdf/139-172/163.pdf http://techpubs.sgi.com/library/tpl/cgi-...i_html/apb.html btw this may help

many 3" radiators have 3 layers of coolant passages while many 2.25" only have two layers, the result is that the coolant flows thru the 2.25" radiator aproximately 30% faster, allowing that much less time for the air to absorb and transfer the heat from the coolant

chevys powdered metal rods for the sbc are significantly weaker than a set of aftermarket (H) style rods with floating pins and FORGED PISTONS that you should be useing in a turbo combo,the forged crank you have is about 40 years old, it may be fine but ID have in carefully checked when the assemblys ballanced with the new rods and pistons (which you REALLY SHOULD GET) keep in mind that rods normally fail long before cranks do, and that the weakest point on most stock rods are those lousy 3/8" rod bolts, aftermarket rods with 7/16" capscrew bolts can be and frequently ARE 50%-to WELL over 200% stronger than factory rods. http://www.cnc-motorsports.com/category.asp?CtgID=4203 http://www.cnc-motorsports.com/product.asp?ProdID=8089 http://www.cnc-motorsports.com/category.asp?CtgID=4203 http://www.flatlanderracing.com/manleyrods-steel01.html http://www.flatlanderracing.com/manleyrods-steel01.html and the great news is they don,t cost much compared to getting stock rods resized and arp bolts added, and bushedc for free floating pins, all that costs more and gets you less in a powdered metal rod with 3/8" rod bolts btw even ported and pollished 882 castings will cost you a great deal of power compared to a good set of heads, on a turbo you might want to look into the platinum heads as they give great potential for the cost http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10002&storeId=10001&categoryId=27305&parentCategoryId=10187&langId=-1 both can be ported, and remember with a turbo and correct gearing you don,t have to worry nearly as much about low air flow port speeds, but the restriction to flow at high boost can be significan with small port heads

yeah we tested these a few years ago on a couple engines, at low rpms the do help smooth the idle and can increase the mileage due too a more consistant and fineing a/f mix,these would work great on a motor homes bbc with an auto trans, but you can feel the restriction on some engines on peak power.

http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?lang=-1&catalogId=10002&storeId=10001&categoryId=18035&searchItemId=41267&CT=999 be aware that they work great at lower rpms, and help gas mileage in a few cases, but restrict flow in the upper rpm range

the 230volt illistration is flat out WRONG on that link! the two hot leads (black p1) (black P2)are correct but the GROUND must be a GROUND(GREEN) vs (WHITE)neutral and MUST be tied to the GROUND SIDE OF THE TERMINAL BOX TO PASS most building code inspections, not the neutral bar, now both will work, but only the correct (black p1) (black P2) (green grnd) will pass inspection in most areas http://www.danielwoodhead.com/pdf/139-172/163.pdf http://leviton.com/pdfs/d-503/d-503T.pdf (pg 20-22) http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/0650/bks/SGI_Admin/books/OrOn2_SitePrep/sgi_html/apb.html most dryiers use a 230volt 30 amp circuit, youll need a 230 volt 50 amp circuit according too the owners manual for that welder, youll need a dual pole 50 amp breaker and space to install it and a 3 or 4 wire 8 gauge romex wire to meet or slightly exceed most building code requirements. if your circuit breakers are located in the garage and thats where you choose to install the 50 amp outlet for the welder it will be very easy to hook it up provided you have the room for the new breaker in the main fuze box

"if you have .500 valve lift, at .250 measured, it should be centered on the valve stem, and at a right angle to it." your correct in theory but in practice its best to have the rocker reach that point at slightly higher PERCENTAGE of the lift (example) ,with that example of a .500 total lift, Id try for center at .300 vs .250 at the 60% point vs the 50% point) simply because the valve spring pressures are much higher at the higher lifts valve lift, yeah EITHER method works and will be better that most engines that don,t get close after a cam swap

get the HARBOR FREIGHT or northern tool, hoods, thier cheap and work reasonably well, ideal, no! but it sure beats dark goggles, and Ive got one Ive used frequently when under conditions that Id rather not subject a better helmet too like welding dirrectly overhead, where crud tends to fall on the helmet http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46092 http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200311850_200311850 THEY regularly sell for $59 -$69 on sale! Ive even seen them sell for $55 once speedglas makes a much better helmet if you have the buck$ https://weldingsupply.securesites.com/cgi-bin/einstein.pl?Next::17:UNDEF:OR:R::PR#R07

a few places to look for plug/ignition info http://auto.howstuffworks.com/ignition-system.htm http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country= http://www.gofastzone.com/techtips/sparkplugs/sparkplugs.htm 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 http://www.rmlautomotive.com/ignition.html http://www.bgsoflex.com/auto.html http://ourworld.compuserve.com/homepages/JET_AV8R/Vision/Ignition/CDI.HTML http://www.howstuffworks.com/ignition-system.htm http://auto.howstuffworks.com/ignition-system1.htm http://www.familycar.com/Classroom/ignition.htm http://www.motocross.com/motoprof/moto/secontent/seign/ignprin/ignprin.htm http://www.northwestautorepair.com/ignitionsystem.htm http://www.boyleworks.com/ta400/psp/distcurve.html http://www.chevytalk.com/tech/index.html heres other options http://www.davessmallbodyheis.com/ http://www.msdignition.com/ http://www.proformparts.com/catalog/distributors_GM.html http://www.atlanticspeed.com/store/MSD%20Chevrolet%20Distributors.asp http://www.holley.com/HiOctn/ProdLine/Products/IS/ISD/ISD.html http://www.performancedistributors.com/gmdui.htm Spark plug /ignition info http://www.edelbrock.com/automotive/sparkplugs.html http://www.ngksparkplugs.com/apps/car_truck_suv/default.asp?nav=60000&country=US http://www.strappe.com/plugs.html http://www.applink.net/cct/tips/plugwires.html http://www.acdelco.com/html/pi_plugs_ident.htm http://www.atlanticjetsports.com/_techtalk/00000005.htm http://www.ngkspark.com.au/spark_plug_cross_ref_chart_index3.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.eric-gorr.com/techarticles/sparkplugs.html http://www.gnttype.org/techarea/engine/plugs.html http://www.tsrsoftware.com/sparkplug.htm http://www.racinghelp.com/read_spark_plugs.html http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp2.asp http://www.gofastzone.com/techtips/Spark...20Reference.htm http://www.geocities.com/zgarage2001/adv...01/advance.html http://www.hotrod.com/techarticles/43300...harticles/43300 http://www.centuryperformance.com/vacuum....com/vacuum.asp http://www.custompistols.com/cars/articl...tion_timing.htm http://chevyhiperformance.com/howto/4567...com/howto/45673 http://www.lmengines.com/Ignition_Timing...tion_Timing.htm http://www.73-87.com/garage/hei.htm]http.../garage/hei.htm http://www.bgsoflex.com/auto.html OPTISPARK info http://www.gmhightechperformance.com/tech/0310htp_optispark/ http://www.charm.net/~mchaney/optisprk/optisprk.htm http://www.fierolt1.com/lt1_95_up_OptiReplace.htm http://www.noid.org/~muttvette/opti.html http://www.gulicks.com/vette/projects/opti/index.html http://www.houston-f-body.org/tech/optispark/ http://www.dynotech-eng.com/dynaspark.htm http://www.corvetteclinicinc.com http://www.corvettefever.com/howto/16758

short answer! the pushrod checker works well enought for 90% of the applications,to get you close enought to run a street combo. but lets look at what your ideally TRYING to accomplish here first! whats the reason we even give a crap about the rockers contact or angle to the valve? well basically the ideal valve train would push vertically in perfect alignment with the valve to minimize any contact between the valve and the valve guide it slides thru to both reduce friction and eliminate wear, so ideally the rocker should push down exactly on the center of the valve with zero side loading. thats going to occure only if the rocker pushes on the #2 location, but since the rocker swings in an arc centered on the rocker trunion or the rocker ball,the tips relation to the valve stem changes. getting the geometry correct minimizes the rocker tip sweep distance accross the valve tip. now roller rockers generally have a roller tip that minimizes the DRAG friction as it at least in theory rolls very slightly allowing the force to remain mostly directly down in line with the valve and have a lower % of force wasted in forcing the valve stem against the valve guide wall.before the valve moves down ward in the guide. http://www.eng.wayne.edu/page.php?id=758 http://www.mercurycapri.com/technical/engine/cam/vtg.html http://www.pontiacstreetperformance.com/psp/valvetraingeom.html http://www.holley.com/data/TechService/Technical/Valve%20Train%20Geometry.pdf#search='valve%20train%20%20geometry http://www.compcams.com/information/Products/Pushrods/

"Any ideas on this stuff holding up to " ID suspect the chances approch ZERO! of a succesful repair on a head,in the combustion chamber, as the melting temp of the alumaweld is below that of aluminum http://www.aluminumrepair.com/more_info.asp Low working Temperature. Between 717 and 737 Degrees Working Temperature. Over 500 Degrees Below Melt Point of Aluminum.......and combustion chamber surface temps in a cylinder head can easily reach high temps under heavy loads, according to several plug manufacturers

while it depends on the ramp design on the cam lobes you could usually depend on getting an insignificant EFFECTIVE increase in durration in the 3-4 degree range ,swapping from a 1.5 to a 1.6 rocker ratio, the durration does not change but the RATE at which the valve accellerates away from its seat DOES change enough to change the EFFECTIVE flow thru the port marginally,but your not likely to see any real benefit untill the higher rpms are reached simply because the cylinders don,t (SEE ) a big differance in flow at low rpms due to the time available for flow into the cylinder. look at it this way,if the cylinders can fill ,any increase in potential flow is just that (POTENTIAL, but UNUSED FLOW.) untill the ports restricted DUE to durration,lift or AVAILABLE TIME, if you have a 7% increase in flow( the approximate differance in peak lift) it will only make a differance if that 7% becomes an advantage in efficiency. at 1000rpm theres a flow pulse thru a port 8.3 times a second, at 7000rpm theres 58.3 pulses per second and the extra 7% potential might help read http://www.gregsengine.com/rocratio.htm http://www.compcams.com/Community/Articles/Details.asp?ID=2132654598 notice theres little change in effective flow into the ports due to the higher lift untill about 3000rpm swapping rocker ratios is a good tunning tool, but if you need a serious change in cam timing a new cam, not rocker ratio changes are needed, you may also want to keep in mind that that increase in rate of accelleration and higher total lift CAN get you into clearance issues and unstable valve train harmonics if your already running close to your limits. swapping to those 1.6:1 ratio rockers on a mild cam usually helps, but once your running at high rpms with a serious cam, its usually better to use a longer durration,higher lift cam with its slower accelleration rates and the lower ratio,rockers to increase valve train stability,or the valve spring pressures required get higher than ideal real fast

I think the (F) advance curve will get the best results if you set it up that way so the TOTAL advance reaches about 35-36 degrees advance , let the initial advance at idle fall where ever it may as long as its in the 6-12 degrees advanced range, (6-9 is normal here)but be aware that crappy fuel octane may get you into detonation under heavy accelleration on hot days

Ive used the ALUMAWELD several times, it works fine if you follow the instructions, but ID only use it on non-structual components like repairing an intake manifold or thermostat housng

sooner or later everyone screws up and cracks or breaks parts, now of course the applications vary wildly.... but in many cases repairs CAN BE MADE heres a few options http://www.aluminumrepair.com/technical.asp'>http://www.aluminumrepair.com/technical.asp http://www.aluminumrepair.com/hts528.asp'>http://www.aluminumrepair.com/hts528.asp http://www.aluminumrepair.com/ http://www.aluminumrepair.com/more_info.asp http://jbweld.net/index.php http://jbweld.net/products/water.php

call MSD 915-857-5200 TECH LINE 915-855-7123 The MSD Tech Lines are now open Monday through Friday 7am to 6pm Mountain Standard Time and ASK! , Ive run the blasterII coil in the past,but IVE also done ALOT of other mods, its best to ASK the manufacturer so you DON,T SCREW it up!