LT1-LT4 Modifications 1993-97 Gen II Small Block V8

De-stroked LT1?

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Old Sep 19, 2009 | 03:20 PM
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Default De-stroked LT1?

OK, just looking for the straight answer to this question, no responses asking why I would want to..

Does anyone make a 327 crank to fit the LT1? meaning a one piece rearmain seal crank...
I would like to destroke an LT1 to a 327. Is it possible without a custom crank?
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Old Sep 19, 2009 | 03:23 PM
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You can use a 2-piece rear main crank with an adapter. What are you trying to accomplish though. The stock crank will handle the 7000rpm limitations of the computer plus some and is as good as or better than a lot of the aftermarket stuff. The ONLY reason I could see to even consider this would be a racing class displacement limitation.
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Old Sep 19, 2009 | 03:41 PM
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Didnt think the stock crank would spin that high safely. Also, main reason is that I love the quick and high revving characteristics of the 327 I have (had) in my 85 TA. I want to upgrade/ try something new with a fuel injected engine and aluminum heads, but thought it would be great to keep the 327.
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Old Sep 20, 2009 | 09:49 AM
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not on the shelf, but Callies might make it in the Magnum line.
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Old Sep 20, 2009 | 10:04 AM
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Use the 1-piece seal crank out of the 265 cubic inch Caprice 'LT1' in the 350 block and you'll come out with a 302.
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Old Sep 20, 2009 | 11:35 AM
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Originally Posted by 94FBIRD
Use the 1-piece seal crank out of the 265 cubic inch Caprice 'LT1' in the 350 block and you'll come out with a 302.
The Caprice LT1 has the same bottom end as the F-body. The engine code for the 4.3L is L99.
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Old Sep 20, 2009 | 11:57 AM
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Originally Posted by OnA Fan
The Caprice LT1 has the same bottom end as the F-body. The engine code for the 4.3L is L99.
were you agreeing that it could be used to make a 302? the crank is a 3" stroke on a L99 so the numbers at least make sense.
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Old Sep 20, 2009 | 01:42 PM
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Originally Posted by stevo9389
were you agreeing that it could be used to make a 302? the crank is a 3" stroke on a L99 so the numbers at least make sense.
I just wanted to make sure the OP didn't go out looking for a Caprice LT1 crank. I have no idea what the math for displacement is, but LT1 bore with the smaller stroke would be somewhere between 265 and 350.
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Old Sep 20, 2009 | 02:15 PM
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Originally Posted by 85taracer
Didnt think the stock crank would spin that high safely. Also, main reason is that I love the quick and high revving characteristics of the 327 I have (had) in my 85 TA. I want to upgrade/ try something new with a fuel injected engine and aluminum heads, but thought it would be great to keep the 327.

Don't get stuck in the 60s assuming stock parts are bad.

My Dad thinks 350 cranks are weak and the best SBC ever made was 283, things have changed. I would put the stock crank up against the chinese forged stuff most people "upgrade" too.
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Old Sep 20, 2009 | 03:07 PM
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the stock crank will take the abuse. Im gonna push my 355 with stock crank pretty hard and its the least of my worries
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Old Sep 20, 2009 | 05:41 PM
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Originally Posted by OnA Fan
I just wanted to make sure the OP didn't go out looking for a Caprice LT1 crank. I have no idea what the math for displacement is, but LT1 bore with the smaller stroke would be somewhere between 265 and 350.
Yeah, I forgot the code was L99, that's why I specified the 265 incher. The resulting cubic inches would be 302 with the 4" 350 block.
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Old Sep 20, 2009 | 05:53 PM
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Someone did that, end result was no torque with no positive gain anywhere.

As covered the stock crank will take more rpm than the computer can dish out so this would be pointless unless it was a "class rules" thing.
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Old Sep 22, 2009 | 01:00 PM
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I was curious about this as with the LS1 PCM conversion couldn't one spin to 9k+ RPM? I like watching that tach needle race upwards, now that we could run a LS1 PCM couldn't someone make a 302 like the 69 z28's?
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Old Sep 28, 2009 | 08:38 PM
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Point well taken on spinning up the stock crank... This is why I posted my idea instead of just doing it. Will be sticking with "350" (blah plain jane) oh well.
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Old Sep 28, 2009 | 11:53 PM
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Originally Posted by 96capricemgr
Someone did that, end result was no torque with no positive gain anywhere.

As covered the stock crank will take more rpm than the computer can dish out so this would be pointless unless it was a "class rules" thing.

John Moss and Mark McPhail did the Lt1 302 back in i think '94 and put it in a '68 camaro it was nice however it lacked the bottom-end TQ the Lt1 had but would wind up to 7500 RPM.
So basically they had a modern 302 efi Lt1,cool for the era of the '68 it was put into.
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Old Sep 29, 2009 | 07:03 AM
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Originally Posted by 96capricemgr
Someone did that, end result was no torque with no positive gain anywhere.

As covered the stock crank will take more rpm than the computer can dish out so this would be pointless unless it was a "class rules" thing.
Not knowing the specs and saying this motor didnt have any tourque could have been from many things. Just like the factory 302 that was modified for racing had absolutely no low end which is why GM had a totally different 302 for the street. The reason here is the cam & induction system wasnt meant for lowend but for high rpm power. The 283 was basically the same engine just less bore still had the same issue, using the right combination of parts and they held there own, put a big cam in there and they wont get out of there way till you hit the intended rpm range. Running a cam with a range of 2500 to 6500 in 5.7 vs 302 the cam is going start producing in the range of 3000+ to 7000+ rpm, so you basically lost all lowend tourque, add in headers intended for 5.7, bigger exhaust and even a ported intake & bigger throttle body and you kill the smaller cube motor. I'm guessing that who ever built this L99/LT1 combo went for the big rpm numbers and lost all lowend. But I guess we will never know since we dont have any overall data on the build. Thinking of making a L99/LT1 combo and making 500HP will not be anywhere near streetable as making the 5.7 LT1 500hp, not saying you couldnt do 500HP with the L99 combo but it isnt going to be street freindly by any means unless your doing it with a turbo or other means of power adder.
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Old Sep 29, 2009 | 08:42 AM
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So can the LS1 PCM spin up to 9k or no? Is it impossible to pull this off with a LT1 using a LS1 PCM?
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Old Sep 29, 2009 | 11:08 AM
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Originally Posted by 96capricemgr
Someone did that, end result was no torque with no positive gain anywhere.

As covered the stock crank will take more rpm than the computer can dish out so this would be pointless unless it was a "class rules" thing.
This, but its his decision to have a "fast reving" gutless engine.
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Old Mar 21, 2016 | 02:39 PM
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what if u go carb
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Old Mar 21, 2016 | 02:45 PM
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Originally Posted by Clownface
what if u go carb
Get a gen 1....kinda the whole point of building a LT1/L99 is fuel injection. Or save up the $200 to buy a LT1. Why bother building a L99 if still gonna be slower than a stock LT1?
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