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

400cid+ genII block

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Old 04-18-2008, 05:21 PM
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Default 400cid+ genII block

Hey guys. I hope i dont have this in the wrong section but i have a 96 LT4 Corvette coupe and was wondering about bigger displacement. i know you cant safely bore and stroke a LT motor bigger than 396 but was curious if there was an aftermarket block out there that would let you do it. if you have an LS you can either sleeve ur cylinders to get big cubes or go the C5R block route or get an LSX block. i was curious if we had any kind of options like this with a GenII block that would still accept LT components like heads and intake
Old 04-18-2008, 05:37 PM
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You can go bigger than 396 in a LT1 block BUT the ONLY reason to is to say you have a big engine.

Are you looking for bragging rights at car shows or are you looking to make the car fast?? What sounds impressive to the average car show guys and what actually makes a car fast are not necessarily the same thing.

If money is no object a few months ago someone claimed to have a handful the ONLY handful of LTx "bowtie racing blocks" he may still have them they could go bigger.

I know a guy that modified a Donovan aluminum block to accept the mechanical WP, reverse flow cooling, and opti so that is another option is money flows freely.
Old 04-18-2008, 05:55 PM
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If it's a true Grand Sport Vette, I wouldn't mod that block. I'd find another year Vette block and mod it. But there really is no reason to go over even 383 really, let alone 396. On GenI you used to be able to hit 427, but I don't know if GenIIs can do that w/o only being a short lived motor, if at all.
Old 04-19-2008, 12:27 AM
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Originally Posted by 96capricemgr
You can go bigger than 396 in a LT1 block BUT the ONLY reason to is to say you have a big engine.

Are you looking for bragging rights at car shows or are you looking to make the car fast?? What sounds impressive to the average car show guys and what actually makes a car fast are not necessarily the same thing.

If money is no object a few months ago someone claimed to have a handful the ONLY handful of LTx "bowtie racing blocks" he may still have them they could go bigger.

I know a guy that modified a Donovan aluminum block to accept the mechanical WP, reverse flow cooling, and opti so that is another option is money flows freely.
Hit me up with that line. I have been searching for them for 6 years...
Old 04-19-2008, 12:41 AM
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Originally Posted by 96capricemgr
You can go bigger than 396 in a LT1 block BUT the ONLY reason to is to say you have a big engine.

Are you looking for bragging rights at car shows or are you looking to make the car fast?? What sounds impressive to the average car show guys and what actually makes a car fast are not necessarily the same thing.

If money is no object a few months ago someone claimed to have a handful the ONLY handful of LTx "bowtie racing blocks" he may still have them they could go bigger.

I know a guy that modified a Donovan aluminum block to accept the mechanical WP, reverse flow cooling, and opti so that is another option is money flows freely.
The problem is why go to that much trouble and money with the Donovan and still end up with the opti-crap........ Id ditch that for at least the coil on plug mod if I was spending that much...

Ive been told that larger then a 396 with an LT1 factory block is very risky.
Old 04-19-2008, 06:39 AM
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Originally Posted by 1996man
if you have an LS you can either sleeve ur cylinders to get big cubes or go the C5R block route or get an LSX block.
No no my friend..

I'm still stock Bore and I'm over 400cid..

The largest combo right now that can be gotten pretty easily is the 6.2l L92 or LS3 Block with a 4.000" Stroke Crank, that comes to a 418cid Engine.

I took a 6.0l Ironblock(2500HD Truck Engine) and dropped in a 4.000" Stroke Crank, which came out to a 402cid. That is the cheapest combo that is over 400cid.
Old 04-19-2008, 07:26 AM
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Originally Posted by JUICED96Z
The problem is why go to that much trouble and money with the Donovan and still end up with the opti-crap........ Id ditch that for at least the coil on plug mod if I was spending that much...

Ive been told that larger then a 396 with an LT1 factory block is very risky.
Thing is there are some intelligent folks out there who can identify REAL problems and come up with simple solutions rather than curse good parts and replace them with overcomplicated less reliable parts. He breifly tried an MSD opti and went back to a stocker, he does some small mod to the rotors and then the whole opti has been perfectly reliable for him. Same with the 4L60E. You guys would be a lot better off if you listened to the guys like this who take the road less traveled and actually learn how to do and correct things than you are listening to all the other ignorant kids.
Old 04-19-2008, 10:55 AM
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Convert to a SBC and go with a singel plain with efi conversion or somthing


No point in using a LT1 at that point
Old 04-19-2008, 04:27 PM
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That is what I would like to do when it time for my lt1 to go is replace it with a big inch small block and keep the EFI.



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