When building my '68 I used a 9" dual diaphragm booster and master cylinder combination from Master Power Brakes. The master failed immediately. Could not achieve a pedal when bleeding. The booster failed within one year. It was my only experience with MP Brakes but was disappointing. Switched to a Wagner master cylinder (Wilwood 4 wheel disc) and a Tuff Stuff Performance 9" dual diaphragm booster. Several years later still good. The only MP Brakes component left on the car is the booster mounting bracket.