OK. I'm taking the plunge. I've got a 82 Chevrolet C20 rear axle semi float. It has 13" brakes on it. It has the 4 5/8" width drums. (which measure out 4.94" by the book spec - don't blame me, I'm not the one that created the catalog.
It looks like I can swap all the brake stuff from the 82 onto a 1968 Chevrolet C20 full floating rear axle. The benefits are: 1) It looks stock 2) I can get all the parts. I have EVERYTHING 100% brand NEW ready to install...both drums, all hardware, both adjusters, both wheel cylinders, and AC Delco Durastop NEW shoes. So I will end up with a 4.11 13" brake full floating rear axle that will appear stock looking in the vehicle.
IF this actually works, it will be truly awesome. I will have to take pictures to document it and will post my progress.