66-67 Dodge Charger Source Guide

You'll definitely need to replace the receiver/dryer, it's technically a consumable part. Have a radiator shop check the evaporator, if it's plugged, and it probably will be, have a new one made or buy a replacement. The compressor can be rebuilt like any v-twin, parts are scarce but available. An alternative is a replacement from a parts house, using yours as a core. The ID tags are reproduced, or you could re-use yours if they look OK. Carefully check the underhood (hard) lines for any corrosion, inside or out. Moisture & contamination are the death of an A/C system. Replacements can be made to look exactly like the originals. And have new soft lines made.

As far as refrigerants go, yes, R-134A is about 60% as efficient as R-12 (Freon). Fortunately, it's readily available and cheap. With all-new components it should do fine, but it will never approach R-12 coldness. You V-2 compressor will work with it, but make sure you buy the correct O-rings when reassembling your system. Classic Auto Air can help you out in that regard. Or you could decide to fork over the $$$$ for Freon, especially since your system will be all new & sealed properly.

Or, if you just want cold A/C and don't care about original appearances, the Classic Auto Air systems work wonderfully. It's really a matter of personal preferences & available cash. An entire setup from Classic will run @ $1100 and include everything under the hood, including the evaporator. A correct-appearing system will cost more, but if that's what you're after, go for it. The parts are available.

A friend of mine who's a mechanic at a local Dodge Dealership did the R134 conversion to his 66 Poly Charger. He did the cheapo 'dirty charge' which means all he did was install the 134 fittings and give it the synthetic oil shot and final charge with refrigerant. He replaced no components. He claims that it cools really well.

I also did a 'dirty charge' conversion on my wife's '90 NY'er and it worked great too. I think though that the cooling ability is down a bit from R12.

When you convert to 134, all the old organic oil should be purged from the components. The 'dirty charge' theory works on an empty system based on the assumtion that most of the original oil has been lost from normal leaking. The new synthetic oil for the 134 'floats' on top of the old organic stuff so I'm told.

In putting together a new system, this wouldn't be an issue. I would think a change of EPR and TE valves would help especially if there were replacements designed for 134's operating characteristics.

Classic Auto Air in Florida might be a real good place to start. When I redid my AC, I asked them the same question 5 years ago. They told me that if I had R12 on hand, to just stay with it and use that. I did.

Be careful of an AC system that's been disassembled for extended time. Oxidation inside of tubes and coils is a compressor's worst enemy. The A coil out in front of the car is made of aluminum which will also oxidize inside in the form of a white powder (same stuff sandpaper's made out of). Have an AC shop clean everything out real well, or se if they'll give you advice on how to do it. I used Acetone blown out with dried/filtered compressed air at 60 lbs. Followed by a shot of whatever type of refrigration oil you'll need blown through. Then tape off the ends until assembly. Lastly, get a new drier.