67-72 Chevy Truck Chrome 8 inch Booster with Master Cylinder. Master cylinder is a Corvette style and designed for use with disc/disc or disc/drum brakes. Booster is an 8 inch dual diaphragm which offers better stopping than single diaphragm boosters and holds more vacuum than 7 inch boosters. Kit also includes proportioning valve which will be your choice of disc/disc or disc/drum. The base kit includes standard chrome master cylinder pictured with booster. Upgraded master cylinders (smooth top or ball-milled) are available. Optional master cylinders are pictured separately. Kit comes with chrome brackets, adjustable connecting rod, proportioning valve bracket and chrome brake lines.