Aftermarket Air conditioning units?

$1325 is too rich for me. They do use a nice, integrated under-dash heater/AC box though.

I have a dealer-added under-dash "knee-knocker" box in 2 of my Mopars. My 65 Newport had a York aluminum compressor (common on Fords). It is fairly light and cools well. My 65 Dart had a beastly Tecumseh cast-iron compressor that I won't re-install. A York would fit on the bracket, but I hope to fit an even smaller, more efficient Sanden shorty. There are add-on brackets to convert mine to a Sanden, but that is clumsy, so I will try a bracket I got from an 80's 318.

If you "roll your own", as I may in my Valiant, I see under-dash units for ~$100 new on ebay, and even less for used vintage ones. They are self-contained w/ blower and expansion valve. You just run hoses/tubes to the compressor and drier bottle. I see new condensors for $50 on ebay, in many sizes for rods. I can make crimped hoses myself, but you can also get that done fairly cheap at hydraulic shops. In the engine bay, the dealer used hose clamps, which works. I use a butane coolant, which works well, but others imagine extreme hazards, so research for yourself. I used R-134A before that and it worked OK.