I believe that '53 has a one year only bell housing for the Powerflite that allows it to be mated to the same engine as the Fluid-Torque trans. '54 has the newer style bell housing that is PF only. I've driven '53s with both trans, and I think the Fluid-Torque is quicker than the Powerflite, even left in high range. My '54 is slow off the line, but her rear end is a 2.93 instead of the original 3.54, so she's built for cruising, not street racing. Cheers, Roger