I can get a 1993 rear with disc brakes and 3.23 posi with 60,000 miles for $300. I got a 1986 trans am with a 9bolt and disc brakes. What do I have to change or do to make that 1993 rear fit in my car?

 

Nothing, or, the wheels if you don't want them to stick out...

 

I'm getting wheels off a 99 camaro so that won't be a problem.
Thanks for the response!

 

You'll need spacers on the fronts to run the '99 wheels on your 3rd gen.

$300 for a 1993 rear? Too much! I got mine for $225, from a 2000 LS1 car, with 3.42 posi gears and LS1 rear disc.

 

where is everybody getting their 4th gen rears??

 

Ummmmmm....... 4th gen cars? Iunno, just a crazy stray thought, I could be wrong though....

Seriously, they come from wrecked cars, usually. The place to find wrecked cars is your friendly local junkyard. That's where I go to find stuff like that. Last time I was in the one by where I live, there were about 3 of them just kind of hanging out, waiting for a new owner or to be melted down.

 

We got most of ours from friends that upgraded to 9" or 12 bolts.

 

same here.
if you hang out on 4thgen boards, you'll find that "stock" rears are basiclly worthless... if anyone tried to sell me one(without brakes) for over $100 id have to laugh.. brakes are worth ~80 to 100, so for a total swap around $200 max... (keeping in mind my prices are local to where i live.. cheapass southeast.. add some if the cost of living where you are is higher.. lol)

most 4thgens have a posi and atleast 3.42s... not all, but most do.

 

Thanks for clearing that up, I was convinced they came out of old Vegas....... If i switch to a 4th gen rear, will I have to use anything else to use my stock 90 trans am rims?

 

Your stock rims will fit fine - just stick out further in the rear than usual (assuming they are 16's - might have issues with 15's and rear disc brakes). I just lucked across mine I guess, I wasn't looking hard, but just kept my eye out for anyone locally parting a wrecked 4th gen car.