4. 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. The diagonally split system is used on front wheel drive cars where 85 percent of the braking is done with the front wheels. For greater braking capability (as opposed to front to rear split), one front and one rear wheel will always be stopping the car.
5. You can see from the bumps in the lid which chamber is larger. The chamber nearest the mounting face is for the front disc brakes (larger chamber). This chamber can also be used for front drum brakes by retaining the residual check valve for that chamber.
6. Adapters shown on the end of the two brake lines (and in the outlet ports) will be needed, since the ports are larger than the 3/8-24 brake line fitting. The right port is 1/2-20 thread, while the left port is 7/16-24.