Hy Egghead, welcome, please post your trucks serial number so we know for sure what we are talking about. Your picture seems to indicate you have a two ton truck and your front fenders if original to the truck indicate a newer truck than a 1942. The machine work is something only you can check on to see if someone in your area can turn your drums and reline your brake shoes. I don't think the parts will be impossible to find for the stock braking system. As far as the dual master conversion, I would rebuild the brakes in their stock configuration first, then you could look at options knowing the rest of your system is in good shape. Hope that helps.
