Huge Bore, Tiny Stroke
Le Mans Master
Joined: Aug 2001
Posts: 6,213
Likes: 1
From: South Alabama
Re: Huge Bore, Tiny Stroke (MNJack)
sorry, never mind.. I thought it was going to be the way your sister described her new boyfriend.... or something like that! :lol: MJ
Our local talk jocks on the FM here said it was like "throwing a hot dog down a big hallway" after Tommy Lee got done with her.
(not meaning to hijack... ;) )
Racer
Joined: Nov 2002
Posts: 359
Likes: 0
Re: Huge Bore, Tiny Stroke (TedH)
I'd suggest just finding a sound 327 or 350 and rebuilding it; forget de-stroking unless you are planning for road-racing where a high winding small-block is wanted.
If your friend's heart is set on building a de-stroked engine, have him take a 327 and add the 283 crank (late 283) and you get a 302. Not sure of the rods to use (283 or 327).
If your friend's heart is set on building a de-stroked engine, have him take a 327 and add the 283 crank (late 283) and you get a 302. Not sure of the rods to use (283 or 327).
Abby Normal
Joined: Dec 2001
Posts: 53,385
Likes: 92
From: Press "2" for English
Re: Huge Bore, Tiny Stroke (Simon Alexander)
Would it be safe to assume:
More bore, less stroke = higher horses at higher rpm
Same bore, more stroke = higher torque at lower rpm
?
More bore, less stroke = higher horses at higher rpm
Same bore, more stroke = higher torque at lower rpm
?
Melting Slicks
Joined: Oct 1999
Posts: 2,581
Likes: 14
From: Tolar Texas
Re: Huge Bore, Tiny Stroke (OatBoy)
OatBoy, run this one by your neighbor to see what he thinks about it.
I would like to see someone build a modern 302 based on the 92-96 LT1. Could it be done using the following receipe?
Combine the crankshaft from a 1994-1996 4.3 liter, L99 (Baby LT-1 used in the Caprice) with an '92-'96 5.7 liter LT1 block, rods, pistons and heads.
It would be interesting to see how a modern 302 with roller cam, reverse flow cooling, and fuel injection would perform vs. the old DZ 302.
Specifications (old vs. new):
DZ-302 (4.000 bore) (3.00 stroke) (5.70 rod) (2.45 main journal) (2.10 rod journal)
L99.......(3.740 bore) (3.00 stroke) (5.94 rod) (2.45 main journal) (2.10 rod journal)
LT1.......(4.000 bore) (3.48 stroke) (5.70 rod) (2.45 main journal) (2.10 rod journal)
I would like to see someone build a modern 302 based on the 92-96 LT1. Could it be done using the following receipe?
Combine the crankshaft from a 1994-1996 4.3 liter, L99 (Baby LT-1 used in the Caprice) with an '92-'96 5.7 liter LT1 block, rods, pistons and heads.
It would be interesting to see how a modern 302 with roller cam, reverse flow cooling, and fuel injection would perform vs. the old DZ 302.
Specifications (old vs. new):
DZ-302 (4.000 bore) (3.00 stroke) (5.70 rod) (2.45 main journal) (2.10 rod journal)
L99.......(3.740 bore) (3.00 stroke) (5.94 rod) (2.45 main journal) (2.10 rod journal)
LT1.......(4.000 bore) (3.48 stroke) (5.70 rod) (2.45 main journal) (2.10 rod journal)
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
Re: Huge Bore, Tiny Stroke (MIKER)
The only sane people who de-stroke an engine are those who are limited to a certian displacement by racing rules :rolleyes:
Also remember that large bores increase octane dependancies since the flame takes longer to cross the piston.
Any well built engine is rpm limited not by the crankshaft but by valve float. Even a stroked 400 can run to 7000rpm if the valve train is up to it.
Also remember that large bores increase octane dependancies since the flame takes longer to cross the piston.
Any well built engine is rpm limited not by the crankshaft but by valve float. Even a stroked 400 can run to 7000rpm if the valve train is up to it.
Thread Starter
Pro
Joined: Feb 2002
Posts: 500
Likes: 0
From: sebastopol ca
Re: Huge Bore, Tiny Stroke (427V8)
The only sane people who de-stroke an engine are those who are limited to a certian displacement by racing rules :rolleyes:
Also remember that large bores increase octane dependancies since the flame takes longer to cross the piston.
Any well built engine is rpm limited not by the crankshaft but by valve float. Even a stroked 400 can run to 7000rpm if the valve train is up to it.
Also remember that large bores increase octane dependancies since the flame takes longer to cross the piston.
Any well built engine is rpm limited not by the crankshaft but by valve float. Even a stroked 400 can run to 7000rpm if the valve train is up to it.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Re: Huge Bore, Tiny Stroke (427V8)
Re: 302
Ran a 306 (302 bored) w/ lots of C/R & cam a long time ago. Since I had spent my pre-teens learning engine design, it never was my choice for a mid wt. car. Sometimes one has to run what he can afford. Nevertheless, beat BBs. Wound up running my 4.56 posi full time on the street & running at high speed.
Mine went tore up the block at high speed.
Remember there is no C.I. limit on the street.
A 383+ runs like a BB.
Stroke-Increasing the stroke
Destroke-Decreasing the stroke
Stroker-Increased stroke
Ran a 306 (302 bored) w/ lots of C/R & cam a long time ago. Since I had spent my pre-teens learning engine design, it never was my choice for a mid wt. car. Sometimes one has to run what he can afford. Nevertheless, beat BBs. Wound up running my 4.56 posi full time on the street & running at high speed.
... the power down low, funnier to punch it at 2000 rpm's and burn the tires than rev it to 7000+ and throw a rod through he oil pan. JMHO
[Modified by Fevre, 10:52 AM 11/6/2002]
[Modified by Fevre, 10:52 AM 11/6/2002]
Remember there is no C.I. limit on the street.
A 383+ runs like a BB.
Stroke-Increasing the stroke
Destroke-Decreasing the stroke
Stroker-Increased stroke
Burning Brakes
Joined: Sep 2000
Posts: 922
Likes: 0
From: Maine
Re: Huge Bore, Tiny Stroke (Ganey)
Your friend can do whatever he wants, but you may want to remind him that there's no replacement for displacement.
One of the reasons for short-stroke motors is the limitation imposed by piston speed. Short-stroke motors can rev higher for the same piston speed number. Of course centrifugal loads on the rods go up quite a bit (square of speed I think) which can add $$ to an engine build. Larger bores allow bigger valves thus better breathing. Of course in order to take advantage of that breathing you have to run a more radical camshaft, which is probably going to be street unfriendly.
Just because an engine is capable of producing a lot of power at lower rpm doesn't mean that you have to drive around all day WFO. Your buddy might want to consider a blower setup: he could have his cake and eat it too (so to speak).
One of the reasons for short-stroke motors is the limitation imposed by piston speed. Short-stroke motors can rev higher for the same piston speed number. Of course centrifugal loads on the rods go up quite a bit (square of speed I think) which can add $$ to an engine build. Larger bores allow bigger valves thus better breathing. Of course in order to take advantage of that breathing you have to run a more radical camshaft, which is probably going to be street unfriendly.
Just because an engine is capable of producing a lot of power at lower rpm doesn't mean that you have to drive around all day WFO. Your buddy might want to consider a blower setup: he could have his cake and eat it too (so to speak).
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Re: Huge Bore, Tiny Stroke (OatBoy)
I went down that road with a 3.25 X 4.060 it was nice , but!!!!!!!!!!!!!
Years ago someone formed a 1/4 drag event here in Reno at the old AFB runway. One of the guys I knew who spent every dollar he had on his 302 Z 28 69 or so camero. It was rare car and he had everything to hop it up. Brodix heads 8000+ rpm choppy idle, aluminum rods, 12.5 pistons, race gas.
I show up at the event in a 400ish hp 355 ci. That I used 6500 as a shift point. His 302 was in a slightly lighter car and a 4 speed. Lets say it had 500 hp out of that screaming 302. (All the Bench Racer knew it was way over 500!) My car back then was a 12.90's at altitude and the best he could do with a high hp zero TQ car was 13.o's. This is also at 5000 feet elevation on a 90 degree day.
We lined up together near the end of the bracket races. Maybe it was the semi's where we finally met up. We had about a .10 difference dial in on the tree. He cut a better light and I still ran him down at half track and passed him by three car lengths and then I was on the brakes for the win nearly right on my dial in.
Him and the bench racers never gave me hell about my wimpy hydraulic cam Vette ever again.
You'll never beat cubic TQ!:)
Years ago someone formed a 1/4 drag event here in Reno at the old AFB runway. One of the guys I knew who spent every dollar he had on his 302 Z 28 69 or so camero. It was rare car and he had everything to hop it up. Brodix heads 8000+ rpm choppy idle, aluminum rods, 12.5 pistons, race gas.
I show up at the event in a 400ish hp 355 ci. That I used 6500 as a shift point. His 302 was in a slightly lighter car and a 4 speed. Lets say it had 500 hp out of that screaming 302. (All the Bench Racer knew it was way over 500!) My car back then was a 12.90's at altitude and the best he could do with a high hp zero TQ car was 13.o's. This is also at 5000 feet elevation on a 90 degree day.
We lined up together near the end of the bracket races. Maybe it was the semi's where we finally met up. We had about a .10 difference dial in on the tree. He cut a better light and I still ran him down at half track and passed him by three car lengths and then I was on the brakes for the win nearly right on my dial in.
Him and the bench racers never gave me hell about my wimpy hydraulic cam Vette ever again.
You'll never beat cubic TQ!:)
Thread Starter
Pro
Joined: Feb 2002
Posts: 500
Likes: 0
From: sebastopol ca
Re: Huge Bore, Tiny Stroke (gkull)
I went down that road with a 3.25 X 4.060 it was nice , but!!!!!!!!!!!!!
Years ago someone formed a 1/4 drag event here in Reno at the old AFB runway. One of the guys I knew who spent every dollar he had on his 302 Z 28 69 or so camero. It was rare car and he had everything to hop it up. Brodix heads 8000+ rpm choppy idle, aluminum rods, 12.5 pistons, race gas.
I show up at the event in a 400ish hp 355 ci. That I used 6500 as a shift point. His 302 was in a slightly lighter car and a 4 speed. Lets say it had 500 hp out of that screaming 302. (All the Bench Racer knew it was way over 500!) My car back then was a 12.90's at altitude and the best he could do with a high hp zero TQ car was 13.o's. This is also at 5000 feet elevation on a 90 degree day.
We lined up together near the end of the bracket races. Maybe it was the semi's where we finally met up. We had about a .10 difference dial in on the tree. He cut a better light and I still ran him down at half track and passed him by three car lengths and then I was on the brakes for the win nearly right on my dial in.
Him and the bench racers never gave me hell about my wimpy hydraulic cam Vette ever again.
You'll never beat cubic TQ!:)
Years ago someone formed a 1/4 drag event here in Reno at the old AFB runway. One of the guys I knew who spent every dollar he had on his 302 Z 28 69 or so camero. It was rare car and he had everything to hop it up. Brodix heads 8000+ rpm choppy idle, aluminum rods, 12.5 pistons, race gas.
I show up at the event in a 400ish hp 355 ci. That I used 6500 as a shift point. His 302 was in a slightly lighter car and a 4 speed. Lets say it had 500 hp out of that screaming 302. (All the Bench Racer knew it was way over 500!) My car back then was a 12.90's at altitude and the best he could do with a high hp zero TQ car was 13.o's. This is also at 5000 feet elevation on a 90 degree day.
We lined up together near the end of the bracket races. Maybe it was the semi's where we finally met up. We had about a .10 difference dial in on the tree. He cut a better light and I still ran him down at half track and passed him by three car lengths and then I was on the brakes for the win nearly right on my dial in.
Him and the bench racers never gave me hell about my wimpy hydraulic cam Vette ever again.
You'll never beat cubic TQ!:)
Le Mans Master
Joined: Nov 1999
Posts: 5,768
Likes: 3
From: San Diego CA
Re: Huge Bore, Tiny Stroke (OatBoy)
There was an article done a long time ago - they put a 327 crank in a 400 block - used a really long rod (like 6.5 inches or something like that) - turns out this combo is really close to 350 CI - they ran like 10.5:1 CR with iron heads and made really good power - no pinging because of the long rods apparently - I'll bet that motor could rev
Advanced
Joined: Aug 2002
Posts: 84
Likes: 0
From: Riockwall Texas
Re: Huge Bore, Tiny Stroke (Cajun75)
There were actually 2 302's produced by GM for the Z-28. The '67 Z-28 had a small journal crank (like all pre '68s), and the '68 and '69 had the large journal crank. Both used 5.7" rods, with different big end diameter. The '68/69 versions were the "Pink" high performance rods.
Using a 4 bolt crank, good rods and high flow heads with a stud girdle will yield a small block which can safely rev to 9000 RPM. Put a 7500 RPM rev limit on it and it will live forever. Just don't miss a shift at 7500, because you will hit 10,000 right away and it might come apart.
This thing is miserable to drive on the street in a 3200 lb car with less than 4.88 gears.
Using a 4 bolt crank, good rods and high flow heads with a stud girdle will yield a small block which can safely rev to 9000 RPM. Put a 7500 RPM rev limit on it and it will live forever. Just don't miss a shift at 7500, because you will hit 10,000 right away and it might come apart.
This thing is miserable to drive on the street in a 3200 lb car with less than 4.88 gears.
