i think stock A body single piston callipers are 2 5/8",a 1 1/32" master will probably be fine.
As stated,i have used 1" master with 2 3/4" callipers ('73-4 E body pin style) and loved the brakes ...everything was new.This was on a '70 Duster
Regardless, the point i was trying to make is that going by the above information, i am enlarging the caliper piston size, and keeping a 1-1/32" manual master cylinder. A 1-1/32" master IS the same bore as stock A body manual disc brakes. According to this information it would yield a softer pedal with a firmer grip at the calipers.
This is the information i needed. I was thinking of going power brakes, but if this gives me a bit of a power feel without the weight, cost and space useage of a booster, then i'm all in. I screen shot that info and stored it in my phone.