It is my understanding that the metering valve is used to restrict front line pressure in disc/drum cars to allow the rear drums to overcome the return springs before the front calipers start to clamp down. In this manner, the brakes are used evenly and wear evenly, otherwise the caliper pads might wear much faster.

Where can I get a metering valve?

I have a 66 Dart with a Ford 8" rear (Ford 10" drums) and I have 75 Dart front disc brakes. I am using the 75 Dart proportiong valve/loss indicator, but I have no metereing valve.

Do A bodies even need it, or is it only used in heavier cars?