Actually, the housing ends changed in '62 for most models. Even though the '62-'64 retained the tapered axle, the housing end bolt pattern was changed and retained when they went to the flange axle in '65. As stated earlier, the big difference is the depth of the housing bore...the '65-later is deeper (about 2 1/4") and the seal is deeper to accommodate the axle bearing retainer.

In the pic below the pre-'62 is on the left.