I'm engaged with making a 1650 from an 1100. This entailed removal of the 4 speed manual Peerless trans and rear and installing the ported hydrostat. When I removed the brake rockshaft (the brake and clutch arms are reversed on the shaft), I needed to drive the roll pins out. I supported the shaft with a jackstand as close as possible to the arm with the base on the concrete floor and the roll pins were easier to drive out.
From reading the postings in this forum, it's unclear if the posters did this and from my experience, you can beat the roll pins til the cows come home without much success because the tires absorb the shock needed to get the pins moving. Perhaps I'm misreading between the lines, but PB Blaster and a 3# hammer along with the support of the jackstand usually work quickly for me. Give it a try!
Happy Cubbing, FFGino