'65 Dart Master Cylinder

Just purchased a '65 Dart with a 360. The master cylinder is shot. It is an older style dual master cylinder. Both reservoirs are the same size, probably from a '67 or newer with drum brakes. My Dart has the '74 discs up front.I'm looking for a suggestion on a new master cylinder and proportioning valve that will fit this set up. I also have 1 7/8 fenedrwell headers. This is not a street car. Thanks.Tom.