I haven't got my engine done for that car yet... On the back burner for a bit, but will get to it some day...
I believe that there is a smaller nose on the torque converter for the early ones and the later ones (I think 68 and newer) have a larger nose. You may need to dig deep into the particulars of that before buying your trans. You need to know which one to go with...
Also, 65 uses the trunion on the drive shaft to trans, where the newer ones used the slip yoke in the back of the trans for the drive shaft...