Proportioning Valves?

Well, first of all they aren't proportional valves at all. The one you have will work fine. They're more like a distribution block with a pressure switch to let you know if there's a pressure difference from front to back. As far as a master cylinder, any one you can find. I used the late model aluminum one. works really well. You'll need a manual brake pushrod. If you don't have one try the adjustable one from Mopar performance. I had to cut and weld mine a couple of times to get the pedal height right. The adjustable one would have made it a lot easier. Don;t forget to use the little rubber retainer for the pushrod. Very important.

don