quick question.

the question is whether or not an e-bodies (1970 'cuda) 8 3/4 chunk can fit into my A-bodies (68' Dart) 8 3/4 rear-end??? i know there is a difference between the two length wise but does that mean that the center chunks are different.....and if they are not different then would is be a simple swap between the two or does someone know of any problems? Thanks in advance......Aloha