360 swap from van to 74 Duster

Who knows how long the 7&1/4 will last. A bigger better is nice but not needed to get out of the driveway. If you have a long tail shaft trans and a 7&1/4 rear the vans driveshaft and front yoke goes to the car with the shaft cut to 49 ? 49&1/2 ? Anyway when you do get something like a 8&3/4 rear the rear U joint and the tailshaft housing gets changed and happy moparing again.