How to tell LT1 block from LT4

[BLK95-Z]

Does anyone know the differences between the two? Were there 4 bolt LT1 blocks also?

Thanks

[IronOutlaw]

I believe the only difference is the number on the block. There were 4 bolt LT1s, I think they came in Vettes.

[popo8]

Check this out Tinch...

THIS ANSWERS IT:

http://www.grandsportregistry.com/lt1vslt4.htm

THESE DEBATE IT.....

http://ls1tech.com/forums/lt1-lt4-mo...lt4-block.html

http://forums.corvetteforum.com/c4-t...ort-block.html

[BLK95-Z]

Thanks man. I dont buy the info in the ls1tech thread, I know there had to be a different block number or SOMETHING to tell them apart. This is the only thread I could find that said there was a casting number difference.

http://forums.corvetteforum.com/c4-t...g-numbers.html

[BLK95-Z]

I believe the only difference is the number on the block. There were 4 bolt LT1s, I think they came in Vettes.

Yes I think this is correct. But whats the LT4 BLOCK casting number??

[BLK95-Z]

The numbers off the actual block Im looking at is V0929ZVA. Can anyone confirm this as a genuine LT4?

[zraffz]

The number off my LT4 block was 10125327, as far as I understand that is the only casting for the LT4 since they were only made for a year.

I don't know where you are finding those numbers but they aren't the casting numbers to identify the block.

[BLK95-Z]

These numbers were found on the deck of the block in front of the passanger side cylinder head. What does yours say there?

[kgkern01]

GM Factory Replacement LT1 engines were typically 4-bolt LT1's as well. That's how I got my 4-bolt block, it was a dealer replaced engine, now its on the stand waiting for an eventual 396 build.

[zraffz]

Hope this helps...
Front of block on passenger deck reads "V0624ZAC". I have various "327" stampings on my block (inside the block where the bellhousing/flexplate mount & on sides of block) and my casting number located on the back passenger side of the block.
I do want to say all the numbers on the block except for those on the back passenger side are insignificant to identifying the motor. I believe they are for things like manufacturing date, factory, etc...