Short answer is that the drums clear the frame on a 1-ton by a more than adequate margin. Maybe tomorrow I'll measure it for you, but tonight its in the 20's out there and I'm too comfortable to get that cold.
A poor picture.This is the axle under my '54 GMC 1-ton. It has 3.42 gears and the pads appear to have been moved. I got this rear under a '50 Chevy 1-ton so I don't actually know where it started life. There appears to be two versions of the internals or bearings depending on when the axle was made. One of these days I need to figure how which I have.
I believe the wheels on it right now are 15 inch, though they could be 16s. They are only rollers. There is plenty of room around the drums for brakes.
The cheaper disk conversion kits do not include a parking brake, so that's something to think about when choosing parts for a conversion.
