lower ball joint and bolts. big upper ball joint-- so either 73~76 arms or adapters for the small joint earlier arms.
naturally all the junk too-- spindle, hub, backing plate, drum.
same as a disc conversion only the other way around with drum things and stuffs. you might be able to make it all work with just the brake parts and no spindle, but i imagine you'd need to figure out the bearings, and then probably drill the backing plate to mount up to the small bolt spindle. maybe. possibly.
i don't know why you'd go to that trouble just to still have drums.