Your trans was casted on April 6th 1962 and was setup for big truck with handbrake/drum mounted on the transmission. You only need to remove the rear bearing cover and replace it with the standard duty cover from 1948 on up to 1966 like this one attached part number 591701, Type in that part number in ebay and one is for sale now.

Input and output shafts are compatible and correct, in actuality, once the drum is removed it (your existing bearing cover)doesn't even need to be removed, it will accept the standard driveshaft yoke but it would clean it up nicely otherwise.

Steve
Attachments
rear bearing cover.JPG (235.95 KB, 179 downloads)

Last edited by sstock; 03/08/2019 7:53 PM.
1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration