I believe it is just under 57 inches, the track to track seems to be just over 61 inches there are no spring perches on the rear end but has what is looks like the remains of a link system. The other rear end is still in the Cuda and has perches moved over but measured up to be a E Body. I have other E Body Danas one out of a 70 and the other in still in my Stock Cuda. Have a B Body Dana in my Challenger.