The Vintage Air valve has a rheostat and an CU controller:
http://www.summitracing.com/pa...HE14nPSbkWIyjJPD_BwE
I have been using it in the MG for years:

My setup for the heater on the Pantera is different then typical. I am using a P2-T2 couple which I made form stainless and it is in the front of the car before it goes into the radiator:

