Great looking car!
When the car was built, there were three a/c compressors which were used. GMs had the GM A-6, Fords had the Tecumseh-type (which most add-on systems also used), and Chrysler had their RV-2 compressors. All worked great and lived a long time, just needing R-12 gas and the matching oil.
GM later evolved into their Wanklel-style flat pancake compressors. All of these compressors had about 10 cubic inch displacement with pulley diameters that kept them at operational speeds that supplied great cooling. At the OEM level, Chrysler A-bodies (Valiants and compact Darts) cycled the compressors as C-bodies did not cycle them, using an internal EPR valve to regulate things to keep the condenser from freezing up. Adding the EPR valve and unplugging the cycling switch would let the A-body systems operate as the C-body systems did.
When R-134a came along, I had a friend in the automotive a/c business. When I asked about conversions to R-134a, he said all of the old factory compressors had enough guts to handle the higher pressures. He said their testing had confirmed that. Others in here have had other experiences with rebuilt units, though. I could not confirm their experiences on other a/c forums. BTAIM
For 1980, Chrysler went to a Denso axial compressor. But by that time, B/RB engines were out of production, so no factory brackets exist that could be salvaged yarded.
I fully understand the "rebuilt it" orientations. Kits do exist for that and if somebody does it that knows how to rebuild an engine, they seem to work well (with very little cyl bore wear, if any at all). Buying a reman unit can be a crapshoot as the number of suppliers of such has dwindled greatly, IF they knew how to do them to start with. Using one of the later universal a/c oils is needed for R-134a gas. As would getting all of the old oil out of the system.
A new receiver-drier will be needed, so this is a good time to wire in a low-pressure switch, as 1970s-era factory systems had. Our experiences with our '66 Newport Town Sedan factory system was that it was a bit over-capacitied (as the factory systems were back then, for consistent and reliable 40 degree vent temperatures in the TX summers, cooling well when .9lb (out of 3.5lbs or R-12) low.
The Sanden compressor is about 8 cubic inch displacment, but uses a smaller pulley for a bit higher operational speed. This gives the needed flow to make up for the smaller displacement.
There are several threads in here on Sanden conversions. Personally, I would lean toward that direction, but it is not a pure swap-out situation as some hoses will need to be rebuilt. Check out the newest thread by "TxDon" on his '66 Monaco wagon, plus a few others.
To me, the Sanden conversion makes sense. Why? Because when you happen into a shop that does a/c work (anywhere), the (generally younger) techs will know what they are looking at when they see it. So they automatically "understand" what they are dealing with. The Sanden is from "their generation", so to speak. It was also designed to handle the higher pressures of R-134a gas, too.
As to the cosmetics of a Sanden, one thing might be to mist some satin black on the compressor body and line connections for a more factory look.
Neither of the options will be inexpensive. Seems like there are a few threads in here on rebuilding the RV-2 compressor, too.
As to finding R-12 gas, back when R-12 was being phased out, there were comments about R-12 being sourced from non-USA producers, which was allegedly inferior (as to component longevity issues) and not to be used. Not sure how accurate those accounts were, all things considered. There were some EPA-approved "drop-in" alternatives to R-12, as others had their own personal experience choice.
Talk to your a/c shop on these things. THEY are the ones who will be dealing with the system in the future and taking care of it. They know (or should know) another shop associate who has converted an older system in the past and their experiences. OR might refer you to that shop.
These things might take some time, but also do YOUR homework online with suppliers of conversions for vintage a/c systems. One can be Old Air Products in Fort Worth, TX. There are also a afew others, which might be more local to you.
Do your research and keep us posted on the results,
CBODY67
