when switching from all drums from a single resivoir master cylander u need a proportioning valve that goes with it i am planning on doing the swap myself i grabbed the master cylinder and proportioning valve in one peice off a 75 dart
I think your right but thats a distribution block and not a proportioning valve. My Dart was four wheel drums with a duel master. When I went front disc brakes I kept the distribution block and had to add a rear proportioning valve.