Upgrade your car to a 1 in. dual bore master cylinder with our quick install 1964-66 Mustang master cylinder upgrade kit. This 1964-66 Mustang master cylinder upgrade kit allows you to upgrade your factory single bowl manual brake car to dual bowl manual brakes in no time. In this kit you receive the brake lines necessary to route from the new dual bowl master cylinder to your factory 3 port distribution block. Additionally we include a union which will be installed to your rear brake line with the hard line supplied. A great 1965 Mustang master cylinder conversion kit with a factory look and easy installation! Designed for 4 wheel drum brake applications.