Like the title says, which rear? Im running with a 2.8 and i have some 4th gen wheels to put on my car and would like to upgrade to a newer rear with discs. Ive search and seams like 3.73 would be what I want but no 4th gens came with that.... So what my next best choice? I have drums now so im guessing ill need to get a p. valve, or maybe the whole brake system from a 4th gen.... I know people have done the swap but i cant find the info. Also from what car should i look for the "next best" rear?

 

I do believe that some of the Z28s, Formulas and Trans Ams came with a 3.42 geared rear end. That would be the best factory gear. Beware though, some of the earlier Z28s and Trans Ams had a 2.73 geared rear so that GM would have an easier time meeting CAFE requirements.

I got the rear out of my car from an '88 GTA trans am, and I got the brake master cylinder and proportioning valve with it. I put new rear rotors on there, new brake pads, bought some poly bushings, and swapped everything in. Of course I was reusing my original wheels.