What heads, planned compression and planned octane? That will effect stall and rear gear chosen. A TH350 can be built strong enough, make sure it isn't a TH250. The factory 7.5" is weak, start with replacing the factory soft spider gears, first weak link. Yukon makes a good replacement. Gears depend on the engine and also where you plan on driving the car. Good modern, lightweight forged pistons should help the bottom end survive and be more efficient with a thinner ring pack than something like Speedpro forged pistons. Many believe restrictors are BS. The pickup for most deep pans require a bolt on pick up which mean a high volume oil pump. Not a bad thing with a deep pan. The Performer intake is better for mild builds. Are you going with a TBI or SEFI? You need G body 260 or 307 frame mounts to install your 455. Good luck.