The rear would be a simple remove and replace.

I'm no brake expert, but Chevy also went with a larger master cylinder in 51, 1 1/8" bore compared with 1" in 50. Also decreased the size of the brakelines to 3/16" from 1/4" in 50 (except for the line from the MC to the first junction block)so not sure if you'd be better to switch those out also. The Hucks in my 50 stop as well as the Bendix in my 51. Just a little more of a hassle to adjust them.

Bob