15/16 master cly
I found one at a local car show. The box has 2 numbers on it.. 11516 and F79772. Check with NAPA, they might be able to cross reference one of the numbers. Your best bet might be the adapter and the 2 bolt MC. I hope that helps. One word, don't let them (NAPA) tell you the early drum brake MC's interchange. THEY DO NOT! There is a residual valve in the rear bowl to hold 10 lbs of back pressure on the brake shoes. If you try to use it you will find your disks locked up, ask me how I know. There might be a way to remove the residual valve and maybe someone here knows. Good luck!