Some help might be if you go over to MyMopar and download the 70--72--73 service manuals and look through them. I have found some reference online that some cars also used a prop valve PLUS a metering valve. I cannot confirm that as factory as I simply don't have info on that
Yes. But what is meant by metering valve is not a proportioning valve. It's to hold off the front brakes at the very lowest pressure to reduce front lock up on ice. Never used on A-bodies AFAIK.
List of which cars got which 1970 Chrysler Hydraulic Brake Service Guide p.9
