Compatibility between power and manual disc/drum master cylinders

mvh said
From 67 to 72, the bore diameter was different between power and manual, but not in the way you'd think was logical.

The manual brakes had a larger bore, which made for more pedal effort (1-1/16 or 1-1/32", I forget which). The power brakes came with a smaller bore, making for less pedal effort (15/16").

The "pedal effort" part is not true. You are not accounting for the lever ratio in the stand-off brackets of the power brakes.

>1"D bore sounds too much for manual brakes. I recall that my 65 Dart had a 1"D bore for either manual or power brakes, but check rockauto.

I have never seen a rebuilt manual MC that did not come with the pushrod and dust bellows already installed.

I suspect that a manual MC would work for power brakes. You might need to adjust the tip of your booster output rod to match the piston (should do anyway), assuming yours has an adjustable rod (some do).

You could probably use a power MC with manual brakes, but most don't have an internal groove to capture the rubber bushing on your brake rod. I don't know that it needs to be secured. I will use a power MC (from 90's Mopar) as a manual MC on my 64 Valiant. The rod length comes out correct. I posted photos showing that a few months ago.