The correct diff ratio should be 3.45:1. I had three and that was in 2 out of the 3, the other one being a 3.64, but all the books I have seen all say 3.45. On the auto trannys, from what I have heard and seen, but not owned myself, the B/W is better than the early Z/F but not as good as the later one used in the E-12's. If you have to do it again, I would probably scout around and figure if the linkage and driveshaft will fit from a later Z/F out of a E-12. Mike W.