short stroking high revving v8

[tannji]

cool... appreciate that, Maichor. That was the thing I missed most from back in the L28 days, being able to rev it out a bit more. Especially with my TPI motor....

[dr_hunt]

I'm going to throw in my 2 cents worth, probably not worth much, if that.

 

Many of you members are probably too young to remember the 327 in it's heyday. Most of you have probably never owned one. Ditto for the 283 or the 302. Many a 350 was left in the dust by a 327. Remember Grumpy Jenkin's 331 pro stock '72 vega turning 8K plus running 9's.

 

Nascar and other racetracks are the testbed for what we simpletons end up with from summit, jegs, etc, etc, only down the road. Why is it then that Nascar is using SB2.2 with 4.125 bore and 3.25 stroke with Honda rod journal sizes, turning 9500 rpm for 500 miles? Because for racing it works better than anything else.

 

High rpm isn't what kills engines, it is valve train harmonics and part failure that kills. Of course there's always stupid stuff that kills, but by and large, part failure is the main problem, be it valvetrain, piston, wristpin, rod, whatever. Everything has limits, but if it is built right it'll work, if it isn't, simply, it won't. If you want to turn 7500 rpm then build it for that, but don't take stock parts in a small cube engine and try to turn it past it's limits. Rev limiters, stutter boxes, whatever you want to call them are a good thing for the absent minded of the day. Set limits and stay within them and no matter what you do, if it moves, sooner or later it'll fail. That's why nascar has qualifying engines, race engines, etc. and all are always new parts, not one race old parts. The law of averages will catch up with you sooner or later, and 500 miles is not alot of miles, just hard ones.

 

Best street engine? Whatever your mind will ponder and your pocketbook will let you assemble. Best all around?? Subjective question littered with personal preferences. But there's nothing like the sound of a sbc going above 7K, sounds magical, mystifying and wicked.

 

An old man told me once, that if I was willing to part with something, sell or trade it so I could buy something else I wanted, that I'd be able to experience more without breaking the bank. Nothing you build will last a lifetime, only for a few years anyway, so build a 327, 302 or something like that, run it and sell it or trade it, then buy or build a 406, 421, 434 or something like that. I've built alot of 434's for circle track that turn 7800 all night long, all season long. I've built and owned 283's, 302's, 327's 350's, 377's, 400's and one 434, from mild to insano. Liked them all! I was way, way, way, way impressed with the 434 in terms of seat of the pants ride, scare the shit out of you acceleration, due to monster torque and HP. Then again the 327 never says never and keeps pulling and pulling like the energizer bunny.

 

Another note, I've got 10 small blocks in my shop, including a dart block, several aftermarket cranks, carillo, eagle, C&A rods, etc., etc. There is something to be said for aftermarket blocks like world or Dart, but really only when building monster cubes in the SBC. By the time you deck it, align hone it, bore it and hone it with deck plates, clearance it for big stroke and rods, install deck plugs, hard block, etc, etc, you have 1200 in it already. If you have to tunnel bore the cam, forget it, go aftermarket, it is a better product and will at the very least, give you better ring seal. You 400 sbc guys know all about that already don't you?

 

David

[Guest grom111]

waht would it be if u use a 350 crank in a 400 block with 6.2 rod length on and i mean as in cubes

[dr_hunt]

377 if it has .030 overbore. Rod length doesn't affect displacement, only improves rod to stroke ratio, which in turn adds some benefits like reduced side loading on the piston skirts and slightly increased piston dwell at TDC.

[cremmenga]

WoW!! i have learned alot about 400's from this thread. But the time has come, in 2 weeks a junkyard where i live is closing down and auctioning off everything including several 400's, they said they would prob. only bring about $50 each thank GOD!! Ok here is my plan i have a 1972 240z I plan on putting a 6 speed tranny from a camaro/firebird in it with a i think 400ci. I want to make a pretty reliable car with around 400hp. I will occasionally use this on the ralley course, but more likely at the stop light or on the 100's of miles of flat straight roads I live near. I need to have a pretty damn fast car to eat the f-bodies, the vettes, mustangs and the occasional exotic. what should i set up, should i even buy a 400? Please let me know the auction will be here before i know it!

[Guest 305240]

I have a friend that builds his own engines. He runs a 400 in his circle dirt track car and a 400 in his 70 camaro drag car. His dirt car will run away from the 350s that are built simply because of the torque. The competition will knock him out as soon as they can so they will stand a chance. His drag car will turn towards 8 grand, running as low as a 12.21 et. I asked him one time why he doesn't put his drag engine in his dirt car. He told me it wouldn't hold up. Whatever combination of parts he uses really works.

[grumpyvette]

having just RE-READ this thread ,I think many guys are missing a few important points...some may be confusing the rate of rpm increase with the peak rpms and opperating range of the differant combos, while these little question that a shorter stroke combo can opperate at a higher EFFECTIVE AVERAGE RPM range if properly cammed, that in no way means a shorter stroke engine can accellerate the car faster, or that the shorter stroke engine can build to that range faster once the drive train is engaged given equal rear gear ratios

first the engine moves the car and accelerates the car while under load when its firmly connected to the drive train,the potential extra torque that can be applied from both the longer leverage and greater displacement of the larger engine useing the same bore size, if correctly matched to the drive train gearing allows the greater amount of fuel/air mix and the pressure this generates on the piston surface to accellerate the car faster,

(you might want to think about driving a large stake into the ground, with your choice of a 3lb hammer or a 12 lb sledge, you can hit many more strikes per minute with the smaller hammer far faster but the greater impact per strike still has an advantage)

yes before someone points it out your correct the shorter stroke combo USUALLY runs a HIGHER GEAR RATIO to allow it to build RPMS faster, but thats mostly because it needs the extra mechanical addvantage that higher ratio supplies to move the car with its lower torque levels, and the shorter stroke combo usually has a narrower torque curve and needs to be shifted more frequently and yes a shorter stroke usually can potenially make more hp per cubic inch of displacement, "but more hp per cubic inch of displacement" does not mean more TOTAL HP!, its rare for larger engines that are correctly set up to make less hp that similar smaller engines with a similar combo, and in those cases its comon to find the parts combo is restricting the larger combo!

the greater the CONSTANTLY APPLIED AVERAGE ROTATIONAL torque, (horsepower) in relation to the cars weight, the faster the car will accellerate, yet theres little if any torque applied durring gear shifts so keeping the engine power firmly connected to the drive train is much more effective than constantly shifting gears to stay in a PEAKY torque curve.the engine can REV or build RPMS only as fast as it can accellerate the car!!! and larger displacement , increased compression,and longer stroke within limits helps here, the short stroke combos lower tq and higher rpms along with lower vollumetric efficency ,at those higher rpms and the need to shift more often and potential valve controll problems at high rpms DON,T TEND TOO HELP much

each engine will have its peak and average torque/horsepower determined by several factors but the ability too efficiently fill its cylinders and burn the A/F mix, converting that pressure on the pistons into rotational force is always a ballance between the increased NUMBER of power strokes as the RPMS increase and the loss in cylinder filling efficiency ONCE the engine reaches its peak vollumetric efficiency (the PEAK TQ will usually be very close to that RPM point) and its rarely above 4500rpm-5500rpm in any engine youll be driving on the street, at only 6500 rpm the engine needs to fill EACH of its cylinders over 54 times PER SECOND, it does not take a great deal of thought to realize that the time necessary to fill the cylinders gets excessively to short as the RPMS increase much past that RPM RANGE, and it just so happends that a 3.75" stroke of a 383 or a 406 sbc reaches 4000fpm in piston speed at 6400rpm (usually considered the max breifly sustainable RPM for stock style parts due to inertial stress limits)

example

heres a race style 350 that makes over 500hp, yet the torque peaked at 5500rpm, only the increased number of power strokes of constantly lower effecincy as the rpms build above that rpm keep the hp number climbing FOR AWHILE, UNTILL the TORQUE VALUES fall off faster than thre increased rpms compensate for

now read this build up

 

 

now both engines would make a fast car, but CORRECTLY GEARED the larger engine with its lower average rpm range would be BOTH FASTER and MUCH MORE REASPONSIVE

[grumpyvette]

BTW

 

http://ohiocrank.com/

 

check out the 454 SMALL BLOCK ENGINE for $7000. or $4000 for a short block, assembly,at that price its almost not worth building your own, and just buying it already built, especially if your not in possesion of all the tools/skills necessary

Id bet a 450hp/550 tq engine would be quite interesting in a (Z) and ask anyone whos built a 450hp ENGINE for thier (Z) Id bet they got less for their money???

OH! I bet it RPMS quite nicely due to the tires having damn little traction to slow them down, if your running street tires

 

454 Cubic Inch Chevy Pump Gas Small Block

 

On our Superflo dyno this motor made 455 HP with an amazing 550 ft. lb. of torque. It idles great, runs on 92 pump gas, has good throttle repsponse and driveability. This would be the ideal street rod small block. It features a Motown block, 4340 steel crank, H-beam rods, forged pistons, Canton pan, Sportsman II heads, Motown intake, and roller rockers. It's just realy cool to have a 454 SMALL block in your hotrod.

 

$6995