64 Dart A/C

Integrated factory air with the heat, defrost and AC controlled by the 5 push button unit in the dash started in 65 as an option. What you call factory air (the underdash unit with it’s own controls) was either dealer-installed or aftermarket. Other than taking up some real estate, there’s nothing wrong with that type of AC unit. For the Underhood parts, the factory V twin compressor (although a heavy SOB) works just fine as does the other compressors of that era or use a late model Sanden compressor. Aftermarket driers can easily be sourced as well as lines and the condenser. Not even Vintage Air makes a bolt-in kit for the early A’s. Try running a search in the heating AC section of the forum for pics.