Limited Slip, and Gear Ratio?

[Unit 5302]

I take it you have a 1988 Mustang GT auto. You can use an 8.8" rear end from 1986-1993 LX and GT 5.0 for the Mustangs as bolt in replacements, and the later Mustang GT's as well, although they will be wider. Also the 1987-1988 Ford Thunderbirds, which again, will be wider, Turbo Coupes and I think 5.0s got 8.8" rears from the factory in those years. The Turbo Coupe has rear disc brakes as well. The best ratio for an auto is probably 4.10:1. None of the Mustang's, Tbirds, etc came with 4.10's, but the auto 1987-1988 T-Bird Turbo Coupes did have 3.73's. The standard gear for the Mustangs was 2.73 and the optional 3.27. There is more info I can give, but what are you planning here?