Okay, so I know this is problably a really stupid question, or series of questions. I've never done any work with the rear end of a car before, but I'm interested in changing the gear ratio of a 1992 Firebird L03. How difficult is such a switch? Does it neccesitate changing the entire differential? If not, is it easier to do so?

Also, what would be a good gear ratio to choose? Or if I need the whole differential, what are my options? I could lay hands on a 1986 2.8 auto. (I sold mine, but the junker has a couple), which has 3.42s, I believe? Would this fit, would it increase performance much?

 

you can do it either way, change the entire rear or just swap gear sets. if you've not got the right tools the rear swap is by far easier and cheaper than buying tools.