I faced similar issues with 1" and 7/8 on rear. Ive got Ford D60 w/ dual piston calipers and 14 bolt w/ chevy 3/4 tons and wilwood 7:1 pedal. I switched to 3/4 mc up front w/ residual valve and 7/8 in rear. After tweaking the pedal bias some it was night and day difference. Basically what I learned after buying 3 different MC's is the larger the diameter of the caliper piston(s) smaller MC bore size.