Good News:
I removed the huge rear drum from my 3/4 ton ‘53.
Here’s how I did it:
1) Removed wheel cylinder bolts and pushed on unit through openings in rear brake plate. ( actually used long bar and hammer )
2) Using 2 lb hammer I repeatedly hit sides of drum until it started to move. Some of these blows were glancing so as to add a turning force.

Note: I tried Unsuccessfully backing off Star wheels - very difficult access and these were stuck. No movement here.
Use goggles and don’t crack your drum.