I am running drum brakes front and rear with an under floor style non power master cylinder on the roadster pickup. My master cylinder bracket will accept either Ford or Chev master cylinders. I have a single reservoir chev master cylinder that I was given by a friend, but rather than rebuild it I believe I will go to the parts store and buy a rebuilt or new dual reservoir unit. Since I am not running discs on either end of the car, and pretty well all new cars/trucks have discs or disc/drum combinations, I am not sure what year and bore diameter to look for.---can anyone help?