The common disk conversion kits are all designed for a 1/2-ton truck. The spindles are different on the 3/4-ton and the 1/2-ton kit isn't going to work the way it comes out of the box.

Unless you are commited to keeping the truck a 3/4-ton you might consider swapping a 1/2-ton axle in the front so you can benefit from the available conversion kits instead of designing your own conversion.

I'm curious why you would choose a nailhead for this swap. Starting in '55 GMC installed Oldsmobile and Pontiac V-8 in pickups. I've always thought a fun swap would be a 455 Pontiac with the GMC pickup valve covers and GMC labels.


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...