The bottom end from 87 - 92 used forged pistons, 93-95 used crappy hypereutic (sp?) pistons. If you plan on a 450 rwhp you won't be using the stock bottom end anyway.
Frankly you're going to have to run about 8500 RPMS on a 302 to make anywhere near that kind of rear wheel power, and the stock block will last about 2 passes down the strip before it explodes, so you if you actually want to make that kind of naturally aspirated power with a 302 you had better scrap the stock block idea and go straight to an 8.2" Dart block.
Adam