early a master cylinder swap

The fruit jar MC, you'll recognize one when you see it!. My exp: 65 dart with 9" drums up front/9" drums in rear alum dual MC, everything new. was woefully inadequate adjusted correctly & even had the shoes arced to the drums. 2nd 65 dart with 74 A front discs (2.75" calipers) with aftermarket (ceramic?) pads and later 7&1/4 rear, not sure of the shoe width but it is 2" or wider & OE shoes, kept the OE drum splitter. stopped excellent, no excessive pad wear, definitely the way to go. never did figure out what was wrong on the 9" drum setup, went over everything just never felt like enough braking force was being put out to the 4 corners. On the 13/16 rear wheel cyls, some parts houses supercede you up to a larger dia cyl but on paper it says 13/16. bring a 6" steel scale with you & peel back a boot