Why is everyone obsessed with converting everything including the kid's coaster wagon to disc brakes? If drums were as obsolete and dangerous as everybody seems to think, there wouldn't be any of these trucks left to restore- - - -they would all have been wrecked before they were 5 years old! A 1 ton is a commercial vehicle intended to run all day with a maximum cargo load, or more likely, a pretty good overload. I don't know of many, if any stovebolters who intend to run around on a routine basis with 2,000 pounds of anything on their trucks. Stopping a more or less unloaded truck with the original brakes should be a moot point!
Jerry