Help me find a disc brake master cylinder

Go to rockauto.com and order one for a '73 Duster 340 with power disc brakes RAYBESTOS Part # MC36406. That will get you the smaller 15/16" bore master cylinder for less pedal effort and is a direct bolt on to a manual disc brake car. That is what I run on my manual disc brake car. Greater stopping power with less pedal effort. The factory calls for a 1" bore master cylinder and its a horrible set up that requires excessive pedal effort to stop the car.