I did it on my '68 a few years ago.Slim said:can it be done without frame mods and sprocket line up w/o hitting inside of frame?
Use the stock hub, spacers, etc. You'll have to dish the rim appropriately to have the tire clear the chain. You will NOT be able to center the rim in the fork. Instead, it must set a little to the right so that the tire clears the chain.
You can run a 130 in most brands, and possibly a 140 for a few brands with a little monkey work and a close fit.
I can't imagine having room to fit a disk brake setup however. Where there's a will (and a welder) there's a way.