I heard this from my Freshman Latin instructor (owned a 1966 Coronet)
"Chrysler products, you either swear by them or swear at them."
I hear you, amigo.Last month, I put a new ignition lock in the Demon. For the first time since I bought the car, it can now with a single key and the column can be unlocked. I connected/disconected only the battery, now Demon is inert and I have a show two weeks hence. I now have lights coming on where there weren't rany. The worst of it all, with the battery connected, the horn blows when the drives door is opened. Fratzog razzlefratz ! ! !
On your proportioning valve, try to position it as close to the stock location as possible. There are several on the board who have quoted Pascal's Law of hydraulics which says with regards to a proper system says it does not matter where it is. Same pressure all over the system regardless of where pressure is applied.
In the real world I know, because I have seen it not be true with regards to one brake system. I helped a couple of guys with the relocation of a prop valve on a 67 GTO due to interference with a set of headers. The lockup point on the rear wheels changed. Rear wheel lockup occurred with less pedal effort than before it was moved.