proportioning valve

Go with the Wilwood or Mopar Performance (same part, different stickers) plumbed into the rear brake line. If you snag one from a donor car, it might not work right and/or it's designed for that weight and handling characteristics of that particular car. With a new adjustable one you can adjust to suit your car.

I plumbed mine under the drivers seat (outside under the floor) and I can just stop, open my door, reach underneath and adjust, then take off again. It's great!