I have a 57 GMC 370 LCF. It has 2 wheel cylinders per wheel for a total of 8. Fronts were different from rears. I never did find a master cylinder, just rebuilt it myself. Bought a NEW Hydrovac from a guy in Morris, Il. cheap as a rebuilt one. His business is Midwest Power Products, name is Rich, nice guy. The wheel cyls. and brake lines came from NAPA. After about $1000 I have great brakes!
