Sorry guys if this was already asked, but would a 350 block from an 89 iroc be the same 350 in the 4th gens? I know the opti is one difference, but I'm not sure about any other differences. I'm looking to buy another LT1 block for my build and someone on craigslist said he is selling an LT1 but he said it was out of an 89 iroc so I'm not 100% sure.

 

He could have put a LT1 in his I-ROC. That isn't uncommon.

 

Yeah I thought about that but I just want to make sure by asking you guys in case it is the stock motor from that iroc.

 

Why not just buy a LT1 block. They are not that expensive if your just looking for the block to start with. Or are you talking about a short block.

 

Well the guy is selling a short block, but I've been trying to find an LT1 block near me. He was the only guy to reply to me so far. I'm not going to immediately jump on it, but it's a good deal.

 

I dont know about using a short block from a TPI car. Yes it will work but whats that going to do to your compression and things like that. Not a big LTX guy but i am guessing they use a similar but different bottom end. Meaning it might work but is it going to be the best combo.

 

Well its a short block, but I only need the block itself. Lol I guess I should have specified that. I would take the bottom end out and sell the crank, pistons, etc. I only need a block to start with.

 

its probly a lt-1 the first lt-1 was nothing like the lt1.

 

Dang, and the newer LT1s are also reverse cooling. Well someone else just replied to me saying he has an LT1 4 bolt from a Vette. If it is a factory 4 bolt, will a machine shop be able to fill the outer holes and splay it back to a stronger 4 bolt design? I know the factory 4 bolts aren't that strong so that's why I'm asking.

 

A sbc 350 wont work with lt1 set up. the reason why is because the coolant ports wont line up between the heads and the block. the heads would have to be modified to make work. I doubt the intake manifold would bolt to small block heads as well.

It could be an lt1 but i doubt it. more likely the seller is confused and it is a l98. the best way to do it is to check the casting numbers on the block. an lt1 block will have a casting number of 10125327 and can be found on the back top of the block like in the picture.


a 4thgen v8 should have either casting number 14101083 for 350 and 14101083 for 305 and neither will work for your lt1 build.

if you were local id give you one for free. but im in Albany, ny