Considering the application, I would use the factory replacement 350/300hp camshaft. It will idle great, and make TONS of low end power with a broad power curve. They are available thru most auto parts stores, including NAPA, part number CS-274.
Rebuild the carb to stock specs with one of our kits, and use the stock jets and metering rods. Replace the power piston spring as well, most of those are rusted and/or weak due to age.
Bottom plugs will be leaking, seal them up during the rebuild, we sell a kit for them......Cliff