This is a new 11" brake booster and master cylinder compatible with most A, F, and X body vehicles. 1967-69 Camaro and Firebird. 1968-74 Nova. The high quality master cylinder is set up for disc/disc, disc/drum, or drum/drum applications and is a 4-port unit (9/16" and 1/2"), making it possible to mount your lines on either side.