Larry, I just finished helping a fellow Stovebolter with a brake job on a Huck Brake set-up. You are right, the Bendix parts are cheaper. I think you have to weigh how many times you are going to be changing those shoes and wheel cylinders before you recover the costs of the change.
GL is correct, you will need new backing plates and new hardware. I am not sure if the Huck drum will fit the Bendix backing plate either.
If this is a truck that gets driven as much as most 50 year old trucks, buy the Huck parts. They will probably last ten years or more before they need to be replaced..
Check out Kanter Auto Parts.
www.kanter.com That is where we bought Huck wheel cylinders and shoes. The guy on the counter had to check on them and get back to me in a couple of days, but he did come up with the parts.. As I recall they were cheaper than Jim Carter..
Good Luck