[Dave1695]

You went the wrong way on both rear wheel cylinders and master cylinder bore size. Smaller wheel cylinders will push harder on the brake shoes and a smaller bore master cylinder will generate more line pressure, at the calipers and wheel cylinders. Use a one inch bore master, 7/8th inch bore wheel cylinders and check line pressure at the bleeder screws. you need minimum 950 to 1100 PSI at front and should get 800 to 900 at rear without any adjustable proportioning valve in line. Plumb the master cylinder direct to the brakes for maximum pressure.