grumpyvette

both can be fast but the blending of both tech, can be the fastest, keep in mind a 383chevy V-8 turbo thats built to handle 600-800hp is under far less stress that a 4-6 cylinder engine of 1/3 to 1/2 that displacement making similar hp at far higher boost and rpm levels http://www.vetteexplorer.com/cgi-bin/mv.pl http://www.montygwilliams.com/turbochargers.html but without a turbo a 383 can easily get a (Z) into the 11s in a 1/4 mile,how fast are you planing to drive on the street? SMOKEY YUNICK built a 1200 hp chevy turbo V8 with only about 208 displacement, a 383 will produce a far wider and higher torque curve than a smaller engine and dont forget that a large port set of heads and NITROUS on a 383 and a good short block and cam will cost less that a 600hp plus import engine

years ago mothballs were made of a mixture of campfer and ether several other ingreadiants that dissolved in gas! do yourself a big favor, drop 6 mothballs in a clear glass jar and let it sit in gas overnite, (Ill save you the trouble youll have partly dissolved SLIME, that will clog ANY gas filter) not the ideal way to go faster. heres info on boosters http://www.vtr.org/maintain/gasoline-octane.html http://www.gnttype.org/techarea/misc/octanebooster.html http://www.team.net/sol/tech/octane_b.html http://www.turbofast.com.au/racefuel12.html http://www.diabolicalperformance.com/hotrodoctane.html http://www.pricechemical.com/nitromethane.htm http://www.stanford.edu/~bmoses/knock.html http://www.dynopower.freeserve.co.uk/nitrous_oxide/

glad your paying attention heres what it says "Lobe Center Angle is the distance in degrees between the centers of the lobes on the camshaft. To increase duration, cam makers grind the lobes wider on the base circle of the cam. This makes the lobes overlap each other more, increasing overlap. More duration = more overlap. To increase overlap without changing duration, cam makers will grind the lobes closer together, making a smaller lobe center angle. Less lobe center angle = more overlap" the " This makes the lobes overlap each other more, increasing overlap. ITS SIMPLY A mis-print it should read This makes the lobes overlap each other less, decreasing overlap. spreading the LSA decreases overlap with the same duration, narrowing the LSA increases the overlap with the same duration, look at the diagram again as a general rule youll have a smoother running engine thats got a wider tq curve if you stay in the 110-114 LSA range, 406s and 383s with carbs and 4.56 rear gears and single plane intakes tend to gain a slight advantage from 106-108 LSAs but not enought to make up for the rotten idle in a street car!

here read these http://victorylibrary.com/mopar/cam-tech-c.htm http://victorylibrary.com/mopar/header-tech.htm this is some of the best basic cam info youll find so read this first, http://www.newcovenant.com/speedcrafter/tech/camshaft/1.htm (lessons 1-8) http://www.mercurycapri.com/technical/engine/cam/lca.html http://ctfba.tripod.com/main/technical/cams/cambasics/cambasics.htm http://ctfba.tripod.com/main/technical/cams/cambasics/GraphAttack.htm http://moparjimsgarage.virtualave.net/camvalve.html http://www.federal-mogul.com/speedpro/camshafts_speed_pro.html look closely at the duration used for each MATCHING rpm range. ALSO KEEP IN MIND THE DCR AND OVERLAP MUST MATCH look here these are the valve timeing overlap ranges that are most likely to work correctly trucks/good mileage towing 10-35 degs overlap daily driven low rpm performance 30-55degs overlap hot street performance 50-75 degs overlap oval track racing 70-95degs overlap dragster/comp eliminator engines 90-115 degs overlap http://www.symuli.com/vw/camp1.html but all engines will need the correct matching dcr for those overlap figures to correctly scavage the cylinders in the rpm ranges that apply to each engines use range. http://cochise.uia.net/pkelley2/Overlap.html http://cochise.uia.net/pkelley2/DynamicCR.html

http://www.theengineshop.com/engine5.shtml http://www.theengineshop.com/newstuff8.shtml ADD NITROUS

got this question in the email and on another location so heres a good answer how do you adjust valves at idle without the mess of oil getting all over the engine and headers HIT A FEW YARD SALES, SWAP MEETS UNTILL YOU FIND A DIRT CHEAP SET OF TALL CAST VALVE COVERS LIKE THESE you simply cut the ribbed center section out of the valve cover, and glue the synthetic valve cover gaskets on them in the normal location, when you go to adjust the valves you first remove the standard valve covers and install your VALVE ADJUSTMENT COVERS, they retain about 80%-90% of the oil that would normally be lost over the edge of the cylinder head while adjusting a running engine, they also catch much of the splashed oil, just leave a 1/4"-3/8" of the rolled top for strenth around the perimiter of the top surface. I bought my set for $10, they were old and slightly discolored but I could not care less! I took them home and used a drill and saber saw to remove the center ribbed area, theres several brands that are very similar in appearance, all will work! and Ive used them for over 25 years, if I remember correctly they are mickey thompson brand now if the lifters are hydrolic of course you just back the adjustment nuts off the rocker studs with a wrench, slowly until the rocker starts clicking , then slowly tighten the nut just up to the point that the clicking stops then add 1/4 to 1/2 turn to preload the lifter and move to the next rocker and repeat, the only differance with solid lifters is you use a feeler gauge inserted between the valve tip and rocker after they click slightly,to measure the lash distance recomended on the cam spec. card (normally .016-.028 thousands) and you tighten them just to the point at idle that the clicking stops... then you remove the feeler gauge and move to the next rocker if your useing jam nuts dont forget to lock the allen key

if your not willing to do something simple like fabricate motor mounts, a part that you can buy already made from JTR or make with already diagrams available for them and use an engine that been used hundreds of time what are you going to do when you need harder to make parts like a trans cross member or exhaust system

order a catalog from these guys http://www.midwestmotorsportsinc.com/mms.nsf/pages/Specials they have several 7 and 8 qt kick-out style oil pans some only 7" deep, some complete with pump and pickup of very good quality for dirt cheap prices ($75 pan,pump,pickup) Im useing one modified for a larger 9.5 qts on my 383 corvette now, its every bit as nice as some Ive paid $350 for and even with custom road racing mods to hold 9.5 qts it cost less than $180

I got this question," hey whats wrong, my newly rebuilt engine turns overs so slowly it won,t fire up even with two cars and a charger junping the battery and its a new starter and battery? what do I check?" you left out THE MOST IMPORTANT INFO OF ALL. are the battery connections tight? are you getting fuel and spark? (in the correct amounts and at the correct time?) is the engine ignition timed correctly? have you tried a few shots of starter fluid? is the engine bye any chance 180 degrees out of time? or just slightly too far advanced? what does the voltage at the starter read? (durring cranking?) will the engine spin easily with no plugs installed? what are your valve train clearances piston to valve clearances rocker slot to rocker stud clearances retainer to valve guide clearances what were the piston ring to slot clearances? 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? spring bind height/total cam lift and remaining clearance valve lash/preload ? main bearing clearances? piston to bore clearances? ring end gap clearances? thrust bearing clearances what is the main bearing run-out clearance piston to head clearance? rod bolt to block clearances? what tq reading is necessay to spin the crank with no rods attached? did you check the block for a strait main cap alignment? what size journals ana what bearings? are the journals checked for finish and run-out/tapper? did you use moly lube to assemble? did you pre-lube before start-up? did the distributor gear fit the cam gear precisely? 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? were the rods resized? checked for parrallel bores/were the rods strait? were the rods checked for length? was the rod to piston pin side clearance checked? 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/ did the head gasket overlap the bore? is there any coolent in the bores? 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? were the valve to valve guide clearances checked? was the cam drive checked for free rotation and drag/ cam to timing cover clearance? cam journal to cam bearing clearances? was the cam journal run-out checked? were the spark plug threads of a installed spark plug extending into the combustion chamber? was the cam degreed in or just lined up useing factiory index marks? was the cam lobes/LSA/LIFT CHECKED? and are you useing a GEAR REDUCTION TYPE STARTER for EXTRA POWER or just a stock chevy starter? have you tried a differant starter? is the transmission in neutral?

for medical purposes only (LIKE WHEN YOUR SICK OF LOOKING AT THE DAMN VETTE FOR THE EVENING!!)

those peanut port heads you ported will support about 480hp/520tq with those flow numbers and matched to a good intake make a fine torque monster engine if you get the compression up to about 10:1

SPIIRIT you left some tools out of your redneck tool box how can you get by without.... duct tape an acetolene torch PB, blaster spray and a 6 foot pry bar a hi-lift jack and a 45 colt pistol for drilling holes and old car rims for jack stands and a milk crate for sitting on! don,t forget the first aid kit super glue for sealling cuts on your hands and a qt of wild turkey to take away the pain!

RARELY DO I FEEL LIKE CRYING, but I got a question asked... "is it ok to use a large hammer and block of wood to beat the damper back onto the crank when doing a cam swap" that question gets me that frustrated heres the basic installation tool look at the picture carefully, the tool is available from several sources http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=3324&prmenbr=361 heres how to use it... the small 7/16 thread ,on the tool threads into the crank, the damper slips over the tool, the large washer style bearing slips over the tool followed by the solid washer followed by the large nut that threads on the tool, the back of the tool is normally a 9/16 or 5/8 hex this is held with a box end wrench to keep the engine from turning, the large nut is usually a 1 1/8" nut and it is tightened with an open end 1 1/8" wrench or a adjustable wrench against the two washers drawing the damper onto the crank snout! lube the threads on the tool, the inside of the damper and crank snout with oil before starting. the damper will normally slide on about 1/4 of the way bye hand then the tool is needed to draw the damper on the last 3/4 of the distance, don,t over tighten the tool the 7/16" thread will snap off in the crank after the damper bottoms out on the lower timing gear if you do!, NEVER USE A HAMMER AND BLOCK OF WOOD TO DRIVE THE DAMPER ON, YES THOUSANDS OF GUYS THINK THEY DID IT WITHOUT ANY PROBLEMS BUT... IT WILL DAMAGE THE THRUST BEARING CLEARANCES, IT CAN BREAK THE ELASTOMER TORSION RING ON STOCK DAMPERS IT CAN CAUSE THE INERTIAL RING ON FLUIDAMPER TO BECOME JAMMED INTERNALLY IT CAN CAUSE THE DAMPER TO FAIL. IF THE DAMPER FAILS THE CRANK WILL EVENTUALLY BE DAMMAGED IT GREATLY STRESSES THE CRANK SHAFT IT CAN DAMAGE THE CRANKS TRANSMISSION PILOT BEARING IT CAN DAMAGE THE TRANSMISSION ALMOST EVERY TYPE OF DAMAGE IS NOT SOMETHING THAT SHOWS UP RIGHT AWAY, BUT IT WILL DAMAGE THE PARTS LISTED AND THERES THOUSANDS OF GUYS THAT ARE WONDERING WHY THOSE PARTS FAILED 6-24 MONTHs LATER WITH NO CLUE AS TO THE CAUSE! ASK YOURSELF THIS QUESTION, IF CRANKSHAFTS THAT ARE A FEW THOUSANDS OUT OF LINE I.E. NOT PERFECTLY STRAIT ARE BENT/STRAITEND WITH A LEAD HAMMER BY CRANK MANUFACTURES (and yes thats how its done) AND CRANKS THAT ARE DROPPED ON A CONCRETE FLoor SOMETIMES BEND SLIGHTLY ,(happends all the time) WHAT MAKES YOU THINK THAT BEATING ON THEM WITH A HAMMER AND A BLOCK OF WOOD WONT DAMMAGE THEM? AND WHILE WERE AT IT WHAT WOULD YOU DO TO SOME GUY YOU CAUGHT BEATING ON YOUR ENGINE BLOCK WITH A HAMMER? WELL WHAT DO YOU THINK THE CRANKS DOING TO YOUR MAIN CAPS WHEN YOU BEAT ON THE CRANK? PROPERLY USED THAT INSTALLATION TOOL CAN EXCERT OVER 15 TONS OF PRESSURE TO SLIDE THE DAMPER ON, IF IT WONT SLIDE ON, THERES A PROBLEM! FIND IT AND FIX IT .....DON,T BEAT ON THE DAMPER/CRANK ...........if your cranks not threaded GET IT THREADED next time the cranks out, in the mean time pack the crank snout in dry ice and the damper in boiling water.....once both at at the correct temp. spray the inside surface of the damper with LIQUID WRENCH and using pot holders, to prevent burns slide it quickly onto the crank snout before the temp differance equalizes, and yes it may take a few wacks with a plastic hammer but genrally it slides on easily UNTILL the temp differance equalizes

pete think about it a second.....a ZO6 corvette has 405 hp and weighs about 400lbs more than your (Z) should weigh, now a ZO6 can run mid 12s in a 1/4 mile and hit 160mph and has much larger tires than you can fit in a (Z) wheel well, with your extra 75hp and lighter weight TRACTION , not LACK OF HP will likely be your problem look heres a ZO6 dyno,(do you think youll have problems running faster?)

pete, install that crane #114681 6 degrees retarded and look at the results, I think youll be better off in that youll loose a little wheel spin tq but gain a little higher rpm pull!

wtexasZ you know damn well what I ment, any fool knows the 5500 stall converter does not need to reach 5500rpm to move the car, but Im sure you will also admit that the first time you forget and get on the gas even alittle hard while useing stret tires while comming off a light your going to chirp those tires a whole lot worse than a car with a 3500rpm stall converter. and stop and go traffic will be miserable with a converter speed that high, Ive got a 3500rpm stall converter in my vette, and even thats a TOTAL P.I.T.A . in 5mph bumper to bumper traffic we all get into at times

"Might be a close race if the 350 has a 5500 stall converter" yeah that will make for a really nice to drive street combo! (5500rpm stall) stall speeds above about 3500rpm or rear gear ratios much above 4.11 even with an overdrive trans tends to make for a less than ideal street combo! I can just see you explaining to the local cop that your tires just naturally break loose at every stop light, and that its natural for your engine to hit 7000rpm at 30mph

heres a 350 that makes 517hp heres a 383 that only makes 503 hp! now figure your cars gearing and trans keep you in the 4000rpm-6500rpm range at all times, is there any doubt as to which engine will push the car faster?

first IM assuming your looking at the 114681 cam? 1. Why is the "mid-range" performance seemingly dwelled upon more than the upper range in many cases (like this card does)? the engine spends more time in the 4000-6000 rpm range than in the 5500-7000 rpm range so thats where you must concentrate your effort for the engine highest efficiency And then, just what kind of "Performance" are they talking about? max efficiency filling the cylinders resulting in peak tq It seems to me that the upper range would always be more imprtant because of the waning performance due to wind resistance? wind resistance is the result of car speed not where the engine is in the rpm range, for peak performance you want the engines rpm range durring gear shifts to fall very close to peak TQ and not exceed peak HP by a great deal on the upper rpm rangeIs this statement made just to go hand in hand with the "Moderate Performance Usage" statement also made? And I wonder why they don't offset the statement "rough idle" with a comment on it's indication of a stronger high end? "rough idle" refers to the use of the cam in the mythical average 350 engine,as the displacement increases the effect on idle caused by overlap and reversion DECREASES . 2. The 0.026 valve lash reminds me of the old flathead fords we set at 0.014. I presume the extra 0.012 is for the additional overhead mechanisim. It also remimds me of the ability to open or close the lash up to 0.008 to get more torque or rpm as the case required on the oval track. always follow the manufactures suggested clearances (PLUS OR MINUS A FEW THOUSANDS) they spend thousands of hours testing and they KNOW what works best in most applications 3. LIFT: I am not critisizing when I say; why would they carry out a lift number into .0004 (4 ten thousandths)? The total lift does look moderate but I have another question when it comes to the exaust figure being larger than the intake as shown here. I have read that the Ford heads have poorer exaust porting than the chevy and thus require more lift there. I wonder how much greater this lift would be for a ford in this instance? the exhaust valve is smaller and tends to like slightly longer durration and higher lift at some rpm ranges if the exhaust system is restricted 4. CAM TIMING: .002, .006. .050 and now .020? This is a new one to me. Why not the good old .050? Is this .020 pequliar to the manufacturer? Ya, that duration is something else! I would expect a "MODERATE" lope....LOL. These numbers indicate a strong "upper range" to me. 5. TAPPET: Now we're talkin', this looks better to me as we move along!.... In fact, very nice! It looks to me like Grumpy has put a "Baby Giant" firecracker in your hands! 6. SEAT PRESSURE/RPM'S: 120 on the intake @ 6800 max. and no float until 7400? (with mechanical roller tappets I would hope) With that seat pressure, how can they pull this off? Do you beleive these figures? Do they supply the "Feather weight"/helium filled valves to go with this cam?.....LOL! the cam has exceptionally SMOOTH ramps that work very efficeintly, no I dont think youll get 7400rpm with that seat pressure but 6900rpm is very likely, yet KEEP FIRMLY IN MIND THAT A 406 or 383 HAS A RPM LIMIT OF ABOUT 6400rpm DUE TO PISTON SPEED AND VOLUMETRIC EFFICIENCY falling off at rpms above that 6400rpm so youll almost always shift at or under 6400rpm with those engines 7. CAM TIMING/TAPPET AGAIN: Ok, here is what I expected with the other entry. The question remains...Why @ .020 in the first entry? Is this so the "Ramp" can be verified by comparing both entries? Can you explain? Basically a VERY nice cam for the street I would say. IMHO. ---------------------- I didn't check your optional cam yet, I'll have a look but I won't do a legnthy comment if any. Re. Your last comment about tiresome: As I see it, there are two forms of modifieds running the streets; One likes the stick and a lot of gears so they can enjoy hearing the windup, feel the shift thrusts and seem more a part of the "whole" (It' an esthetic thing) and that's fine! The other is when the mind is drawn more to the specifics of what is happening power-wise and that things can be done here to further satisfy that inner desire to become "ONE" with the machine. Horses are like that. What sort of rides would you expect from; A plug, a quarter horse, an arabian stallion? You bet...You would be prepared quite differently in each case! Heh, we all want the Stallion (but many don't care or recognize it exists). You my friend, have that recognition now (the recognition that Torque rules) and your stallion is in the wings waiting ($$$$$).....LOL. _________________ wide torque curves with wide and reasonably high hp peaks are what I try for, ILL always sacrifice 20hp at the peak, for an extra thousand rpm of very clost to peak TQ

http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=114681&B1=Display+Card http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=119661&B1=Display+Card

ok I was asked to join in on this piston speeds over about 4000fpm almost always cause problems engines that spin over 6200rpm with hydrolic flat tappet lifters or about 7500rpm with flat tappet solid lifters need extensive valvetrain work and rarely last for years data the 383 vs 377 debate has been going on for ever, short answer is the 377 can potentially make more hp per displacement but the 383 can potentially make a wider and in most cases more useful tq curve heres two extremely similar build-ups on DD-2000 changing ONLY the bore stroke and cam to take best advantage of each engines natural piston speed limits RPM.......383hp/tq........377hp/tq . 2000........143/376.......142/375 3000........244/427.......241/422 4000........365/479.......361/473 5000........470/493........466/489 6000........517/453........516/451 7000........487/365........505/379 7500........n/a...............485/340 result, no major advantage for either engine the 383 has a very slight advatage in tq over almost the whole rpm range due to its longer stroke and larger displacement, the 377 has an extra 500 rpm before the same piston speed is reached and better breathing due to its slightly larger bore now you can play with the cams. compression, port sizes ETC. but the results will remain very similar, now why not build a 406 for the advantages of both, useing the 377s large bore, the 383s longer stroke, and an increase in displacement over both heres the same engine as a 406 RPM.......406hp/tq . 2000........157/412 3000........ 262/459 4000........383/503 5000........483/507 6000........527/462 7000........496/372

IF you don,t understand auto transmisions, converters,ETC, read this ,it will help http://www.babcox.com/editorial/bf/bf90054.htm http://www.circledspecialties.com/convertoroperation.html http://www.tciauto.com/tech_info/torque_converters_explained.htm http://home.earthlink.net/~micfly/TC.htm http://www.c4vettes.com/tcc.htm http://www.gnttype.org/techarea/transmission/converters.html http://www.boyleworks.com/ta400/psp/Twisting.html http://auto.howstuffworks.com/automatic-transmission.htm http://www.theherd.com/articles/torque.html http://www.autotransinc.com/stall.htm http://www.converter.cc/technical_discussion.htm http://www.tciauto.com/tech_info/trans_dims.htm http://www.nastyz28.com/transid.html http://www.geocities.com/z28esser/length.html http://www.wilcap.com/webdoc8.htm http://www.prestage.com/carmath/dynochart.asp

ITS NOT THAT HARD AFTER YOUVE DONE IT A FEW HUNDRED TIMES,READ this THEN (1) down load this software (bottom of the page) http://cochise.uia.net/pkelley2/DynamicCR.html heres one just for static compression http://www.turbofast.com.au/TFcomp.html heres one for supercharged http://www.turbofast.com.au/TFcompB.html only dynamic compression counts, the engine compresses NOTHING untill both valves are closed this will also help http://www.iskycams.com/ART/techinfo/ncrank1.pdf some of the best basic cam info youll find so read this first http://www.newcovenant.com/speedcrafter/tech/camshaft/1.htm (lessons 1-8 http://www.mercurycapri.com/technical/engine/cam/lca.html http://ctfba.tripod.com/main/technical/cams/cambasics/cambasics.htm http://ctfba.tripod.com/main/technical/cams/cambasics/GraphAttack.htm http://ctfba.tripod.com/main/technical/cams/cambasics/GraphAttack.htm http://moparjimsgarage.virtualave.net/camvalve.html http://www.federal-mogul.com/speedpro/camshafts_speed_pro.html look closely at the duration used for each MATCHING rpm range. ALSO KEEP IN MIND THE DCR AND OVERLAP MUST MATCH look here these are the valve timeing overlap ranges that are most likely to work correctly trucks/good mileage towing 10-35 degs overlap daily driven low rpm performance 30-55degs overlap hot street performance 50-75 degs overlap oval track racing 70-95degs overlap dragster/comp eliminator engines 90-115 degs overlap but all engines will need the correct matching dcr for those overlap figures to correctly scavage the cylinders in the rpm ranges that apply to each engines use range http://cochise.uia.net/pkelley2/Overlap.html http://cochise.uia.net/pkelley2/Overlap.html http://cochise.uia.net/pkelley2/DynamicCR.html http://cochise.uia.net/pkelley2/DynamicCR.html I was asked about a previous post,my example of how do headers work? what I think your refering to was when I was trying to explain how headers help pull the exhaust out of the cylinders by useing the energy from the previously fired cylinder mass of exhaust rapidly moveing away from the exhaust valve causeing a negitive pressure at the exhaust valve that helps scavage the cylinder. what I said was you can demonstrate that negative presure caused by a rapidly moveing mass by getting a 2.5"x5' long section of pvc pipe hold it horizontally and insert a full coke can with some tape wrapped around it so that it just slides easily into one end of the 5' long pvc pipe, now put your hand over the end of the pipe you just installed the full coke can into and rapidly drop the other end strait down, as the coke can slides too the floor you will feel the negitive pressure on you hand caused by the falling mass. now a cylinders volume of exhaust moveing through a primary header tube works in much the same way, while it weights much less than the coke can its moveing far faster and carries enought energy that the same negitive pressure is formed at the exhaust valve by the slug of exhaust gas traveling in the header primary tube, now ideally if the header primary tube is long enought and of the correct dia. to still contain the mass of exhaust gas at the rpm that matches the cam timeing and cylinder volume,a peak of that negative pressure will be forming behind the exhaust valve as it opens during the rpm range where the engine spends the majority of its time, now temp. cylinder volume, compression ratios,cam timeing and interior pipe dia. all effect the rpm range that this effect peaks at effiency wise but in most v-8 engines a dia equal too the exhaust port and about 32"-39" will put that negative pressure wave caused by the previous fired cylinder at the exhaust port in the 4000-6000rpm range, look at this chart, http://www.engr.colostate.edu/~allan/fluids/page7/PipeLength/pipe.html http://www.engr.colostate.edu/~allan/fluids/page7/PipeLength/pipe.html now figure that exhaust is 1300f or 977k so thats about 25" at 6000rpm and about 39" at 4000rpm to get that pressure wave to work for you scavageing the cylinder(helping to pull exhaust out and the new intake charge into the cylinder.)hers stuff to read, http://www.burnsstainless.com/TechArticles/Theory/theory.html http://www.engr.colostate.edu/~allan/fluids/page5/page5f.html http://www.engr.colostate.edu/~allan/fluids/page5/page5f.html http://www.feuling.com/randd/articles/art11.htm BTW it should be obvious why shorty headers don,t make as much power,....the primary tubes being much shorter are also much less effective at controling that negative pressure wave timeing and strength over anywhere near the same rpm range. read this http://www.mercurycapri.com/technical/engine/cam/lca.html keep in mind the same thing is happening on the intake side of the engine in that properly designed intake ports use the inertia of the coluum of air moveing into the intake/port/cylinder to INERTIALLY RAM the the coluum of air into the cylinders durring some rpm ranges, if the two effects can be matched to the correct cam timeing the cylinders can be packed with more that 100% of the air normally filling the cylinders voluum/space at outside air pressure there bye allowing the engine to build exceptional torque by burning greater amounts of fuel/air mix for its size at that rpm range

ENGINE ANALYZER PRO software I bought. ($490) its a p.i.t.a. to work with but does give very good info! you might want to try the new DD-2003, if moneys tight, its not nearly as percise but still its better than DD-2000 heres other options http://www.engineprosoft.com/ http://www.motionsoftware.com/minigide.htm http://www.rapidline.com/pcver.htm http://homepages.ihug.co.nz/~don_s/software.htm

rod bolts and rods normally fail under tension on the exhaust stroke where theres no effective compression slowing the piston down as it plays crack the whip. you can run an engine useing premium forged parts for very brief times at speeds of 4500fps piston speeds if the pistons and rods are light weight. now on a 4.75" stroke bbc engine thats about 5700rpm. I sure would not exceed 6000rpm if you intend that engine to live long! LOOK here, http://www.prestage.com/carmath/calc_pistonspeed.asp http://em-ntserver.unl.edu/Mechanics-Pages/Luke-schreier/unzip/Tension%20and%20Compression%20in%20Connecting%20Rods%20VI.htm http://victorylibrary.com/mopar/rod-tech-c.htm http://www.grapeaperacing.com/GrapeApeRacing/tech/rodslength.cfm