The non power master has what looks like a one inch bore. I have some basic dial calipers, but they are not profesional grade. I also have 3 or 4 other master cylinders that I can try, but they are all for front disc/rear drum cars/trucks. One is a 1 1/16" and the others are one inch.
Slamming on the pedal barely gets the front tires to skid in the dirt in my backyard. I blew compressed air through the passages of all my spare combination valves and they all seem clear and free flowing. I think that the one in the car should be okay too, since each corner moved a fair amount of fluid when I bled the brakes yesterday.
I checked a website: www.imperialclub.com/repair/lit/films/274/index.html and while it is very old fashioned, there were some helpul tips there.
Jeff