This a a subject that i am very interested in, i am looking to rebuild an LT-1 motor, with some quality parts for street use, i have a new LE-2 setup on the way, and i have a good used LT-1 shortblock. From a machining standpoint, it seems to me that there is no difference, clean and mag block, deck block, line hone block, punch block 30 over, install cam bearings, balance rotating assembly, press new pistons on rods. The internals are different, but i am pretty sure the pistons, rods, bearings and oil pump are the same. I know the crank, cam , and heads are different, what else am i missing?

 

Rear main seal is a 1 piece on an LT1

 

So do GEN 1, 86 and up motors, so i am pretty sure you can use that crank, i think the only difference is the 86 and up has a keyway for the front hub. What else?

 

The LT1 crank also has the keyway for the hub. They just didn't bother to put the keyway in the hub itself. The oil pump drive is obviously different with a stub and retainer, since there is no distributor in the back. The water pump is gear driven. The timing cover and timing set are different. After mid-94 the LT1's use powder metallurgy connecting rods that are actually stronger than the earlier "pinks". The thermostat is a unique design in the LT1. The LT1 has a neutral balanced harmonic damper, rather than a balancer.

Check this article:

http://www.automotiverebuilder.com/ar/ar99928.htm