Power Brake Booster

If your Drum brake system is properly set up, it shouldn't need a booster...... Drum brakes are self-energizing, which means that, as the drum turns it grabs the shoes, and wraps them up, which makes them work harder than you might expect, and as the car slows down, you often have to back off the pedal, earlier than you expected to. jus saying.
If you have to stand on the pedal with two feet, something is wrong. Jus saying.
If you install the right heat range copper plugs for your application, and a high-powered coil, you might never have to change them. Mine had over 100,000 miles on them when I finally took them out for a lock-see. They were fine. I changed them anyway, cuz I already took them out. Car did not run any different. Jus saying.
I have had excellent results with a large single diaphragm booster off a mid 70s Swinger. Jus saying.