Search for Grigg's threads on modifying his 6400. That's probably the best way to go on one of these trucks. The other approach would be to move the cab onto a modern frame with brakes up to the job.

1955 1st GMC Suburban | 1954 GMC 250 trailer puller project | 1954 GMC 250 Hydra-Matic | 1954 Chevy 3100 . 1947 Chevy COE | and more...
It's true. I really don't do anything but browse the Internet looking for trouble...