1970 Dodge Dart Swinger Disc Brake Conversion Questions...Please advise!!

If your car came with 4 wheel drum brakes then it probably doesn't have a prop valve on it. That might just be a distribution block and/or a brake warning switch. They look similiar.

I have a 69 Dart that has the prop valve. I am swithing to the KH disc and I got the proper dist block with my purchase.