I have seen master cylinder rebuild kits listed from 1941-1959. A smaller bore will generate more pressure, and use more pedal travel. A larger bore will generate less pressure, and use less pedal travel.
In English... you won't be getting as much of a workout if you select a smaller bore. 1 inch will stop a truck faster than 1 1/4, with less foot pressure.
I don't know the bore type of the Huck or Bendix brakes. I thought it was 1 inch. Most of the hipo manual brakes use a 1 inch bore.
