What is the correct master cylinder for manual disc
All A-B-E body disc brake MCs were interchangeable thru 72. They all looked the same on the outside, with a wire bale holding the cap, and one large/one small reservoir (the large one being for the front brakes, natch).
The difference was in the bore diameter. A larger bore diameter moves more fluid, and requires more pedal effort. For some reason known only to themselves, the Mopar engineers specified larger bores for manual brake cars than for power brake cars (at least for A-bodies). This is the opposite of what would seem logical.
Bore sizes ranged from 15/16" to 1-1/8" (B-body power brakes). A-bodies used either 15/16" or 1-1/32". The latter is "correct" for manual brakes, and is what I have in my car, but if you have a choice, the 15/16" bore will give you a little less pedal effort (trades off pedal effort for a little more pedal travel).
Unfortunately, most of the sources for brake parts do not even realize that bore sizes are a factor, and do not include them in their listings. So you may not be able to tell what you're ordering. "1972 power discs" should get you the 15/16" bore, assuming they have their stuff together (big assumption).
Thanks for the reply's..i'm going with the two different size resv.