A/C Question...

Factory Air (integrated with the heater) and not the underdash add-on AC wasn't that common. Can't say about the Plymouth side of things but from the info I have, out of approximately 324,000 V8 and slant 65 Darts, 21000 were equipped with factory AC - about 6% of total production. I'd say the same or a similar percentage for Valiants/Barracudas.

I'm adding factory Air to my 65 Dart convertible. Did a template of an AC-equipped donor firewall I had and transfered AC line holes, mounting holes, etc to mine and drilled or hole-sawed as needed. Using the template I cut out a section of the heater area on the donor and welded it in my firewall as the heater/AC blower motor is a lot larger than the just heater motor. The complete heater/AC unit (2 separate assemblies) fits perfect. The only thing you can see dash-wise is the AC vents, which do mount to the lower dash but are considerably thinner than the dealer/aftermarket - very similar to factory AC Darts in later years. The hardest thing to find for the Dart was the integrated heater/AC dash bezel - finally found one and shortly thereafter, found another one. I'm considering doing the same upgrade to my Dart wagon as I have 3 complete heater/AC assemblies. I expect on the 65 Valiant/Barracuda the heater/AC bezel will be hard to find as well (got 2 of them in case I decided to do my Barracuda too).

Interesting point - I parted out a late build (7/23/65) 65 Dart GT originally equipped with a 273/235 motor, 4 speed and original 8.75 with a 3.23 peg leg. Other than a radio, the only option it had was factory AC! Also saved all the factory AC stuff from a 66 slant 6 Dart I parted out.

Edit: I see GaryS mentioned the AC installed in 64s were the add-on type. That would be correct as the integrated heater/AC didn't arrive till 65.