[Brad54]

There are two '60-'62 rear ends: one drop-out center with a rear cover that bolts on, the other is the Dana 44.

The '63-up may have had other options as well, but the most common is the 12-bolt.

As already said, the mounting perches are in a different location between for '60-62 trucks and '63-up.

The panhard bar mount on the '60-'62 trucks is mounted on the axle tube about midway between the center and the trailing arm.
On '64-up, the panhard mount is cast into the center section.
I THINK, but do not remember for sure, the '63 may have the same kind of mounting bracket as the '60-62: on the axle tube.

The Dana 44 was used on just about everything, from every manufacturer from Studebaker to Ford to Corvettes and Vipers.

There should be lots of disc brake kits available for them, IF you can find one for 6-bolt axles.
If not, you can have a set of axles made with a Ford pattern and get some Explore brakes... it's not all a bolt-in, but with some investigation it can be done.
Unfortunately, the coil-spring 44s are hard to come by.

-Brad