Manual disc brakes vs power disc brakes questions

whew..glad i retracted my mistake but i did not say you had a c body and i did not say your car was wrong...i said something is wrong.
i did not realize the correct master was 1 1/32" for the 2.75 callipers but i think
it should work fine.... i have used both 1" and 15/16" masters with 2.75 callipers on A bodies and like them because they develop more pressure than the 1 1/32" with less leg pressure,but have a bit more pedal travel.
As was mentioned your pedal ratio may not allow a master cyl with a smaller piston.