Your 72 has green bearings with snap rings. The current 3.55 has no thrust button in it. I took it out. The 3.23 I gave you will work with Green bearings. I had it in a car that had them. 3.23s will be great in that car. 2.76s in that car and 3.18 is a dog. That is what was in the 7 1/14 rear that I took out.