Weak pedal help

Guys i have a 1963 ford fairlane I’ve installed 4 wheel disk was all drum and no power.Ive also added the CPP corvette style booster and master Cylinder with adjustable proportioning valve.
My problem is a weak pedal i can’t get rid of I’m not getting air out of any bleeders but pedal is weak.I can adjust the booster rod out and it gets firmer.But now the rod is pushing into the Master cyl just a little but if I back the rod off the pedal gets worse.
Also on the adjustable proportional valve do i run it to the front or rear brakes and if valve is ran to the front brakes would that cause the issue.Also the rear pads seem to be firm against the disk I also tried firming them up more for testing by putting something under the brake arm to make the rear pads drag a bit to see if that was my issue.Could I have a bad master from the factory? HELP PLEASE