LT1s (350ci, 5.7L) (considerd Gen 2 SBs) found in 92-96 Vettes (aluminum heads), 93-97 Fbodys (aluminum heads), (years?) Caprices, Roadmasters, Some Caddys (these were all cast iron head motors)
LT4s (350 ci, 5.7L) (gen 2) (aluminum heads) found in certian C4 Vettes (GS etc)
LT5 (all aluminum...