1. The under the floor brake pedal operates this single chamber cylinder on a custom installation. The cylinder is mounted on a bracket between the frame and trans. Notice that the brake light switch threads into the bottom of the casting boss. It will need to be relocated by T'ing it into either the front or rear brake line.
2. This is why you should change your master cylinder to a dual chamber type. If you blow a brake line with the single chamber master cylinder, all braking is lost. With the dual chamber type, only half the system is lost and you can still stop the truck. The dual chamber castings measure about seven inches from the mounting flange to end of the casting. The dual chamber 7/8-inch bore master will increase line pressure and stop the car with less effort than the one inch bore single chamber unit.
3. Late model cars are now equipped with diagonally split master cylinders. That means each reservoir has two ports. The bottom ports (to the rear drums) have large residual check valves, while the top ports go to the front discs. For greater braking capability ( as opposed to front rear split), one front and one rear wheel will always be stopping the car.