If you're trying to do it cheaply then just keep looking for stock stuff. I just wanted to caution you that, for instance, not all monte ss had posi rears. They are out there you will just have to look. Also take a look at pre-88' f-body's for posi units. and for gears you can look at: whatever you find you're posi in to simpify things or, pre 88' f-body's, s10's, and astro vans. You have to watch what series carrier you get though(that's why it's simpler to get a posi with the gear ratio that you want). For factory stuff if you get a 2 series carrier then you will have to run 3.08 and numerically down ratios. A 3 series will work with 3.23 and numerically up ratios. Again all this relates to stock parts and i'm sure i'm forgetting some stuff.
If you don't mind spending the money to buy new stuff then it gets a lot easier. Just have to start with what ratio you want and go from there.
