I used the search function
https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=65175&fpart=1Using Google came up with a bunch of truck pictures of 3600's with disc brake conversion.
http://classiccars.com/81162.car So, there are ways to get it done. While you are right, that a simple solution is not available, there are solutions.
I have heard of people using a P30 front axle for the front
I know that the rear center section was the same up to 72, so rear brakes should be easy.