On my 56 3200 235, I took an idea from the forum and installed an in line valve that I got at Advanved Auto. They had a black plastic unit that had a control mounted on the one side. If you wanted to reverse the valve for the flow it was possible to relocated the cable mount unit on the other side of the valve. I mouned it under the battery box and attached it to the temp arm on the deluxe heater control in my truck. I have a standard heater. I also connected the heat/defrost arm to the flip arm on the front of the heater box. Not enough throw but set for full defrost at defrost setting on control and mix of heat and defrost on full heat. Local TV tech rebuilt the fan switch and I use it to control the blower. Almost like real! The guys here think its factory. Just using here in the summer and the defrost for early morings or evening is most important.
