Universal 7" Single Diaphragm Zinc Brake Booster Application: --Universal style Description: --The booster will bolt up to most street rods, hot rods, and many other vehicles . --It also offers approximately 20% (some say up to 27%) more stopping power. --Standard 2 bolt brake master cylinder on top. --Has 4 bolts on bottom that mount to the firewall with 3 3/8" spacing. Master Cylinder Application: --Fit most GM application.This is Corvette style master cylinder. Description: --100% brand new,high performance --Cast iron coated body,dual ball zinc cap --With a 1-1/8" Bore --The cap is attached by 2 small screws --9/16" & 1/2" Ports on Left Side --will work with any drum/drum, disc/drum or disc/disc setup