I replaced all the gaskets, and the main bearings, the rings, pistons/rods and wrist pins are factory (never removed the pistons) , with the .030 shaved zc head and cams on browntop electronics, it feels alot better than my old motor, im pretty positive the black top bottom end is higher comp than the brown top, the engine thats in the teg now was the one I was PLANNING on swapping into the 79