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I was watching the drags on ESPN today, in the shop, and they showed one of the "new" Pro-Stock Hemi's with its valve cover off. It ain't like older Hemi heads.

Valve arrangement was from front to back, I-E-E-I-I-E-E-I. and the top rockers had pushrods that were above the fulcrums, not below them. The intake valves were almost on the middle line of the heads, not angled twords the top of the head, like older Elephant heads. Also, the heads had individual rocker shafts and pedistals for each valve, like a Boss 429 engine, no multiple rockers per long shaft.

Plugs were still in the center of the heads, like the older design, the the rest of it was new.

They didn't show one of the heads of the engine, just a 10 second look at one on an engine with the rocker cover off. Wish I'd have taped it.

Very interesting. Mopar had a ball stud Hemi they never did anything with, pics were in one of the Pteresen pubs years back, and it looked like that, only with different rockers.
 

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A short stroke big block is great. the 427 is probably the greatest engine chevy has ever made, good torque and excellent revving abilities chevy has poured millions of dollars into the technology behind todays small blocks and I would put my money on a ZL1 427 anyday. just imagine if they would put all that technology into a BB. An all alluminum 32 valve tune port injected 427 or even better use a 4.5 bore for 478 cubic inches.

These forums are great. I am a Drag Boat racer myself and would like to invite all you guys to visit our forums at dragboatracing.com

[This message has been edited by MrDixie (edited 05-28-2001).]
 

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I must have been out to lunch on this one. I thought Chevy Pro Stock motors WERE big bore-short stroke motors. I still do, but maybe I'm wrong.
They do rev them way past 7500 and leave full throttle (against the limiter). I was under the impression that they made something on the order of 1200 HP and around 900 lbs. of torque with a 500 C.I. motor (NHRA). I was also under the impression that they accomplished this using very thought out cam timing and cylinder head and intake runner configurations.
Oh well. I won't be building one in the next week or two anyway.
 

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I must have been out to lunch on this one. I thought Chevy Pro Stock motors WERE big bore-short stroke motors. I still do, but maybe I'm wrong.
They do rev them way past 7500 and leave full throttle (against the limiter). I was under the impression that they made something on the order of 1200 HP and around 900 lbs. of torque with a 500 C.I. motor (NHRA). I was also under the impression that they accomplished this using very thought out cam timing and cylinder head and intake runner configurations.
Oh well. I won't be building one in the next week or two anyway.
 

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Someone is using my name in the posts..

My two cents is this, I ran some computer simulations with a 4.50 bore 3.76 stroke compared to the standard 4.00 stroke and the short motor made BETTER torque (higher average) over the entire rpm band. I run a 439 long rod motor and am extremely pleased with the performance.

A magazine (HOT ROD?)did a comparison between small and big motors of the same cubic inch and the big motor beat out the little one on the dyno and the track, why, because the heads flowed better and the torque was higher over the entire range.
 

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I'll throw my 2 cents in since I currently run a short stroke bbc. Mine is a 4.280 bore, with a 3.600" stroke and a 6.500" long aluminum rod. When I bought this engine it was in a 2500 lb S/G chassis car that ran 9 teens in the 1/4 mile. The final cubic inch is 414. The heads were fully ported 990's with a Victor 454R intake, a Pro-Systems 1100 cfm Dominator, and a .712 lift, 272/278 @ .050 roller cam. This thing in my 3650 lb car was a flat out dog. I neglected to see at what rpm the torque curve began...which was about 5500 rpm. I had to spin the thing to 7800 rpm to go anywhere...it flat out would not 60' since I footbrake race, plus it bogged on every shift as the engine came below the converter stall after the shift.

Over this past winter I swapped the entire induction for 781 oval port heads, Victor Jr intake, 4150 carb, and a much smaller .653/.660 lift, 248/254 @ .050 roller cam. The change was impressive as the port velocity & torque improved and the 60's picked up to 1.56 from the previous 1.74's (no spin either). All this was in an attempt to try and correct for the fact that the short stroke bottom end could not produce enough torque to get all that weight moving from a dead stop, plus have torque to recover from the rpm drop on each shift.

Unless you have specific rules to meet with lbs/cu, I would never consider a short stroke bbc to anyone...it's simply wasted money, for less performance.

BTW, the best this small bbc has run to date is 11.12 @ 122 mph, with a 1.56 60' through the mufflers on 10.5" slicks, bolt-on suspension upgrades, footbrake launch, and a much lower 6900 rpm shift point (10.5 to 1 compression).

Anyone want to trade a high dollar "exotic" short stroke bbc shortblock for a run-of-the-mill 468? lol

Also, high rpm buzz motors get old real quick...you just drive the thing wondering what part will give up first??? rods? pushrods? rockers? springs?

A strong built 468 can easily put a 3500 lb car into the mid/low 10's and only need to rev to 6000 or 6500 rpm and live for a couple hundred passes very reliably.
------------------
Malibu Muscle Racing
79 Malibu
414 ci BBC (4.280" x 3.600")
11.13 @ 121.8 mph, 1.56 60'
3650 lbs.

[This message has been edited by Slowazzbu (edited 05-29-2001).]

[This message has been edited by Slowazzbu (edited 05-29-2001).]
 

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How about a 454 smallblock? HE HE

It's possible.

------------------
1984 4X4 s-10. Soon to have 327 v-8, 3.73 700r-4 with shift kit and anti kickdown valving.
 

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In Drag Boats the pro Gassers which are very simular to prostock I believe(500 cid naturally aspirated gasoline 2 valves per cylinder) utilize the short stroke big bore theory. It takes a lot more torque to move a boat through the 1/4 in 7.5 seconds than it does a car and they usualy spin them around 8500 rpm and make 1000 to 1200 horsepower.
 

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i would go ahead and build a short stroker. when the day arises i plan on using a 502 block and getting a 3.76 inch stroke in it. the reason is the higher reving capabilites.street cars really don't need 500 lbs of torque at 2000 rpm because you'll never hook it up so why not shift it all up the rpm band to make it more drivable.
 

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slowazzbu , was you trying to run that poor motor through the mufflers before you replaced parts?on a high trung motor mufflers kill'em. unless you have the exghaust perfectly designed with no back pressure(which is posible),that motor had no chance. but you did manage to pull more usable power out of it with the parts change,good job.
 

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Yes that was thtough mufflers, but not your street or chambered high restriction mufflers. The mufflers run were both 3" Dynomax Bullet & 3" Straightline Performance race mufflers, both a straight thru design.

The rectangular port initial combination was not lacking in top end high rpm performance or power. That combination lacked throttle response, low/mid range torque, 60's, not enough stall speed, not enough gear, etc., etc. I think the mufflers actually helped by providing torque that the engines inherant design lacked.

The new oval port combination is running basically the same ET's as the older high rpm combo, but is 60'ing a tenth and a half quicker due to much improved low/mid range power...also at a milder user friendly rpm range of 7000 and below.

I am going to be changing to a more efficient converter soon in hopes of picking up a little more ET as my old one was slipping 12 to 14%. Tests with a borrowed 9" lower stall converter provided a .16 in ET improvement, plus 3 or 4 mph. A stall matched converter should provide even a little more improvement.

Given all the troubles of trying to get a short stroke bbc to work in a "heavy" street type car, I highly recommend anyone to spend their money on a mild, yet solid built 468 and they can easily run mid/low 10's in a 3500 lb car spinning less than 6500 rpm...and have the engine last much, much longer.

BTW, I plan to test this weekend with the exhaust removed...given this engine is "only" in the 550-580 hp range, I doubt the mufflers wouldslow it down much, if any...we'll see.
------------------
Malibu Muscle Racing
79 Malibu
414 ci BBC (4.280" x 3.600")
11.13 @ 121.8 mph, 1.56 60'
3650 lbs.

[This message has been edited by Slowazzbu (edited 06-01-2001).]
 

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slowazzbu what gear ratio are you running. That is not that much of a change in the stroke the long rods are hurting you more than the 3.60 stroke. I ran a 3.76 stroke stock length rod motor in a 55chev wagon that weighted 3860 lbs without me and it stormed. The cam was 280-286 at .050 and I ran 5.13 gears. I think if you changed the gears it would work.
 

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hello .my 2 cents worth just started on this forum.i have a 427 bbc bored .060 about 13.5 comp i do rev it pretty high i used to shift at 8500 but now at 8100 easier on the valve train.the engine has steel valves manley severe duty 2.25 and 1.94 cut down to 1.92 .the car weight is 3550 with me in it and it has run a 10.12 in the 1/4 with a 1.39 60 foot with the front tires in the air and spinning i still have the video.this engine has gone to 9200 but it will drop a valve when you do it.if you do want to rev a big block up use carillo rods keep the rods at .002 and the mains no more than .0025. and most important use the comp cams belt drive with the idler wheel i have went over 200 runs at 8100 rpm and have not broke anything .also make sure you buy very good valve springs will need close to 300 psi seated my cam is comp 286 dur @>050 dart intake switching to victor 454r for the labour day weekend and a 1190 demon car is a 70 camaro baldwin motion clone 4.56 gears turbo 400 the 10.12 was with 11.5 by 29 hoosier now have 13.5 by 30 m/t et street they barely fit caltrac system i live 4 1/2 hours from the nearest drag track so it is taking me a while to get it dialed in.having fun amyway.hping for 9s soon maybe labour day myabe not.i do have a 400 hp nos kit if i dont get the nines i will have to put it on.lol
 

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Discussion Starter · #34 ·
Welcome aboard Mike,

Glad you brought my old post back from the dead!

I dearly loved my old junk301 engine, but also the torque of my 406 that is now on my engine stand b/c my new 496 is in my car now.

pdq67
 

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Paul,
I am piecing together a BBC right now that will have a 4.5" bore and a 3.76" stroke.
I like my 427's so much, I decided to build a large bore short stroke motor. I know the trend is BIG motors these days, but I am partial to the 283's and 301's of the old days. Even now, I am much more interested in a 396 or 427 big block rather than the 500+ inch engines.
By the way, I just got home from a 7500rpm, gear grabbin, rubber burnin, ride in my 13:1 compression 427 camaro (burning E85)........talk about happy! :)
Smitty
 

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Glad to see this thread brought back to life. I'm doing my version of a big bore - short stroke engine. CNC Bowtie block at 4.600, Lunati Pro Mod 3.75" stroke crank (499 cubes) , Lunati Pro Mod rods, Isky Red Zone solid rollers with street option, Pro Topline 320cc runner heads, SRP forged pistons with 11.25:1 compression. The cam will have the same .050 duration numbers as the old L-88 (264/270) but .725 lift and I'll run Jesel shaft rockers. Induction is up in the air at this point but I'm looking at one of the redesigned Weiand single plane 4150's and a 1050hp Holley. I'm a month or so from building this monster and it'll eventually find a home between the frame rails of my '82 Corvette with a beefed up rearend and a Super T-10 with nodular case and midplate.
It'll be my street toy that will make an occasional trip to the strip, more for bragging rights than anything else. I'm sure that traction below 30mph will be a joke. What I'm looking forward to is downshifting to third and mashing the loud pedal at 70mph.
Can I get a he!! yeah :D :D :D :D
 

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I told the machinist that's doing the work on mine that when I do the downshift and floor it, I want whoever's in the passenger seat to mess their pants every time...and the driver sometimes as well! I'll keep everyone posted, it'll definitely be broken in and tuned on a dyno. I'm hoping for 725 - 750hp at around 7800.
 

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My name is Dennis Ferrara and I built and raced destroked big block Chevy engines in the 1970 and 1980’s We destroked a 454 to 351 cu inches and it raised the power curve from 6 to 8500 to 7500 to 10,000 and made the same horsepower That motor needed to be run st the higher rpm to keep it in the power range It ran 3 tenths and 5 mph faster than the 400vu engines we ran destroked 410 cu 398. 393 379 and 373 cu using the 409 and 348 cranks the 351 was 4.250x3.050 stroke Yes it worked
 

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My name is Dennis Ferrara and I built and raced destroked big block Chevy engines in the 1970 and 1980’s We destroked a 454 to 351 cu inches and it raised the power curve from 6 to 8500 to 7500 to 10,000 and made the same horsepower That motor needed to be run st the higher rpm to keep it in the power range It ran 3 tenths and 5 mph faster than the 400vu engines we ran destroked 410 cu 398. 393 379 and 373 cu using the 409 and 348 cranks the 351 was 4.250x3.050 stroke Yes it worked
What's the point of making the same power by destroking if it costs a lot more to build (a high rpm engine) ?

This thread is really old and the first response - #2 nailed it.
 
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