Port Sizes: 9/16-18 & 1/2-20. Screw Top Lid w/ Hex Screws. Manual Master Firewall Boot Included. Works for Power Booster or Manual Applications.33/8 Center to Center mounting holes for a truly universal application. The item "1964 1972 SBC Chevy 11 Chrome Brake Booster Oval Top Master Cylinder" is in sale since Friday, July 12, 2019. This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts\Brakes & Brake Parts\Master Cylinders & Parts". The seller is "bro-speed" and is located in Corona, California. This item can be shipped worldwide.