Magnum Swap Transmission Options

If the car already has a 904 automatic and you put a small block 904 back in, the rear mount, crossmember, and driveshaft can usually remain the same, although I always suggest a good replacement driveshaft for any aggressive driving or racing. I saw a few factory driveshafts brake over the years in cars that were not crazy powerful, but always in cars that were beat on pretty hard.