Dave I'm not sure if you need a new carrier to get to 3.55s, but I know you can put a 2.94 posi in. This is what I have, MP sells it & it was what was generally in the cop car M-bodies. It's also not too hard to swap in a B-body 8 3/4, f you are really desparate for performance rear. Rob _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com