bigger bore requires more leg and less travel to get the same result on the slave end. smaller bore = less effort/more travel to apply the same amt of force and a hyd floor jack would be an extreme example on the small bore end. That's on paper & way back (didn't know better) I used a 1&1/8" dual M/C on a DD 65 Dart w single piston discs/10" drums & the pedal effort ain't excessive (& I'm not that strong). Though I do drive easy around town and it will lockkup the rears on a panic stop. Almost forgot the worst , I'm using the orig 4 wheel drum splitter (was in a big rush) and semi met front pads. Neither rotor or pad wear is excessive