I used a set from Master Power brakes on my '37 back in 1999, I don't see them listed now, though. It was a pretty straight forward swap, I did replace all the brake lines, but that was pretty easy. I did not opt for power assist, and I replaced the pressure brake light switch with a mechanical switch on the brake pedal. I found I could stop with a light pedal without activating the pressure switch ( no brake lights). My trucked turned out to have a 1950's front axle, so I had to return the first kit for a different one. If I remember right, it has outer GM bearings, Ford inner bearings on an adapter bushing, GM, mid '70s rotors and single piston calipers. I have a '70s GM A body manual disk/drum master cylinder, with a aftermarket brake pedal assembly. My truck was missing the drivetrain and pedals, so I went aftermarket.
Rear axle is from a '79 Trans Am, 10" drum brakes, nothing to special.
Shop around for kits, most are using the later model metric calipers and rotors, and all will have a special caliper bracket. No other modifications should be needed. Just remember the master cylinder will mount facing backwards, so plumb the brake lines accordingly. I had my switched around, it did not work to good that way!
Joe
