We also offer a rebuilt distribution block part number C7ZZ-2B257-A. This part may be required depending on what your car is currently equipped with. This part is recommended for all 1964 - 1966 disc brake cars. 1967 - 1970 cars already have one from the factory but it is a good idea to replace it. This kit is easy to install and works excellent on both drum and disc brake cars. This is a very economical solution for customers that are looking for an improved braking system along with the added safety of a dual chamber master cylinder. Note: Booster requires a minimum 15 pounds of engine vacuum pressure at idle for maximum stopping power. Some high performance high lift camshafts may not create enough vacuum. Stock engine vacuum pressure is 18 pounds.