A/C to Heat ONLY conversion on 68 Dart Sports Special

Although it is possible to do the conversion there are things to be aware of . The firewall openings are different between A/C and no A/C . A heater box from a non-A/C car will not fit . (I tried it) It is possible to use the heater core from the A/C car , build a box for it , hook it up to the defrost vents and get heat . Use a valve to control engine coolant , manually , and use a DC mini-fan as a blower. I think it would be cool (pun intended)