[Pampered-Z]

There are no aftermarket LT1 blocks. We tried a few years ago about getting a company to build them, but we couldn't get enough commitment to make it worth doing at a reasonable cost. Unless something has changed that they will build the blocks cheap?

A stock block you can push a LT1 to just over 400 CI but I think it needs to be resleeved. most common is to go 396CI and often people hit the water jackets. Also at this point you better have a good block to start with, you taking allot of material out so you run the chance of starting to twist the block. The few guys running in the 8's with LT1 blocks are pulling the bolttom ends apart often as the twisting is causing the caps to walk. You're looking big money to build one right. A certain "unstable" person has a custom girdle for his 396 LT1.

There is said to be a few "special" LT1 blocks out there floating around that GM had custom cast for some project that was dropped and the blocks made it into the public. They were cast with ( I think ) high carbon, thicker webbing, and with 4.25 bores for 454CI LT1s. They only show up rarely and the bare blocks go for very large dollars. The last one I saw went in the $6,000 range.

as already said, LT1 heads also fall a bit short on their flow numbers. if you know of N2ODave, he runs a set of Rich Petty's heads on his 396 LT1, and the cost to convert then to the LT1 block has no cheap process. But he does have a high winding LT!

If you're thinking 900+ HP, there are cheaper and better ways to go that messing wioth an LT1.

I love my little LT1, but if I ever decide to go for the 4 digit HP numbers that first think I'll do is pull the LT1!