All Mustangs with Disc Brakes have a proportioning valve. The original valves were preset from the factory. If you are adding disc brakes, you will need a proportioning valve. This valve is also a great replacement for the original. This Disc Brake Proportioning Valve is superior to the original. This valve is adjustable to control the pressure that is distributed to the rear brakes. It usually will provide a great improvement over the stock valve.
Inlet Attachment: 3/8 - 24
Outlet Attachment 3/8 - 24