Unless you plan on running in or over the 400 hp level, don't worry so much about the rear. My 82 runs 12.90s and a bit quicker on spray with a 79 vintage 7.5 rear set up. It is a C4 auto car, and I don't launch on spray, but it has a couple hundred runs on that axle, and 2 years with Drag Radials. (And yes I have an 8.8 for it, with 4.56's waiting to go in)