88 GTA w/ 9 bolt borg warner 3.27s. What rearend will fit in my car if I buy a used one? I found one from 1970-81 firenird that is posi with 3.73s in it for 400 bux. Will this fit? What others can I buy, I heard that the ford 9" are one of the best. Im looking to get good 1/4 miles but no higher than 3.73s

 

Unless you plan on changing the rear suspension you need a diff from another third gen or a fourth gen. As nice it it sounds picking up one from a second gen or a 9" it's that there's no way to attach the torque arm to the diff without changing the suspension so that it doesn't need a torque arm.

You can buy an aftermarket 9" or 12 bolt from places like Moser, Currie or Strange but expect to pay around $2000 for a complete bolt-in diff.

I ran a stock BW 3.27 geared diff for 2 years with no problems. I was running high 11's at 117 mph with a 383 stroker at the time.