I have a 53 as well and swapped in a motor/trans rearend and driveshaft from a 57 panel of mine. Since the axle on the 53 is under the spring and the 57 has it on top of the spring you have to put a new mount on it anyway...so I did move teh center pin to locate teh axle in the middle of teh fender. The driveshaft was a bolt in with this modification. use the 53 bellhousing to keep you mounts the same , but add the center mount to the 57 motor up front
