For discussion purposes there are three items used on 64-73 Mustangs:
- Distribution block. Has a built in brake failure switch, 67 on.
- Junction block. 64-66, routes brake fluid to the brake cylinders.
- Proportioning valve. Disc brakes only. Reduces line pressure to the rear drums brake.
(Note: New model Mustangs have all three items combined. When told of the three separate item, Ford service employees get a headache, they never heard of a separate proportioning valve (kids!).)
Jim