55-58 Chevy Full Size Chevy Car MBM Front Disc Brake Conversion Kit with Booster/Master Cylinder Kit. Wheel kit features 11"rotors, loaded large GM calipers, caliper brackets, backing plates, washers, dust caps and seals. Brake lines and banjo bolts included and requires 15" minimum diameter wheels. Master cylinder is designed for use with disc/disc or disc/drum brakes. The booster is an 8" inch dual diaphragm which offers better stopping than single diaphragm boosters. Kit also includes the proportioning valve with left mount bracket and lines.