We like SSBC's compact power brake booster designed for '65-'66 Mustangs. It fits like a glove and is easy to install. Here, Richard installs the gasket/spacer, which goes between the billet master cylinder and power booster. Before seating the master cylinder, check the distance between the actuator rod and the master cylinder. Adjust to where the rod just misses the master cylinder piston. Ideally, you will have 0.060-inch clearance. If the actuator rod presses on the master cylinder piston, you won't be able to bleed the brakes.