I just had an earlyer post about how i blew my ring and pinion in my 89 formula. I found a rear end out of a 87 trans am that i can buy. People have told me that the 87 calipers are cast iron and are not as good as the ones one my car now. My question is will my calipers off of my 89 formula bolt on to the 87 trans am rear end? If they do it would be great because i can get the 87 rear end pretty cheap. Thanks for taking the time to answer my question.