I wish something came to mind. My 67--when it was together--I had stock 73/4 Duster calipers/ rotors and semi metallic pads. I did not use the larger what, Cordoba calipers? I also have a disk brake axle out of a Versailles. I used the factory 67 drum master, and simply poked holes in the residual valves. No prop valve. I could squall the tires pretty easy at freeway speeds