2nd gen LT1's timing chain set up is different as like said in the prior post, the cam gear actually drives a shaft that runs the water pump. The Opti (distributor) runs off the dowel on the cam 95-97 (93-94 have a knurled shaft the runs off the center of the cam gear) Heads are different as for the reverse cooling. No coolant flows through an LT1 intake. Block is different in how the heads coolant ports are set as well as the Water pump is held on with 6 bolts, not the conventional 4. Crank, Rods and Pistons can be used in 1st Gen with 1 piece rear main. Heres a few pics of some of the differences:
Upper and lower hoses connect to water pump, Opti under water pump.
3 bolts per side on the water pump
Notice no water jackets in heads, also shaft sticking out of front of timing cover which drives water pump. The little holes where the water jackets usually are located are only dead holes in which the intake gasket plastic retainers push into to hold the gaskets on the head.