I'm not sure there are any 'new' RV-2 compressors to be had anymore, and I've had marginal luck with the reman/rebuilt units over the past 5-7 years. Front seals don't seem to hold up to the higher pressures of R134. I also think there is a temptation to 'overcharge' the system with R-134 to try and compensate for the fact that it doesn't cool as much as the original R-12 system. Also, I've found that the guys who hoarded cans of R-12 back in the day, planning to get rich, have had to come down in their prices, since so many people moved to R-134, thus reducing demand for the old stuff.
I did convert the A/C in my 70 Hurst at my last compressor change, and while it doesn't cool quite as well as it used to, something is better than nothing, and the R134 recharge kits with built in gauge are very convenient. I took it to a 'real' A/C service place to make sure it was properly evacuated and charged on an actual machine, not just a shade tree conversion. I've also found it helps to run the A/C at least once a month, whether it's needed or not, to keep the front seal lubricated so it won't dry out and let gas escape during cold months and/or storage. As always, your mileage may vary. Last year I moved from MA to TX, so I might just be experiencing the fact that a system which performed well enough in 85 to 90 degree weather in the northeast in summer has more trouble coping with triple digit days in Texas in July. The last RV-2 compressor I had was not even engaged or running when the front seal started oozing oil out just standing still while I was parked at a cruise night. Sweaty ride home. I contemplated switching to a Sanden, but I had a spare RV-2 'new in the box' from Rock Auto sitting on the shelf, so I went with originality. If this one fails in less than 5 years, I think I'll go Sanden with one of the readily available brackets for a 440 install, plus the required new hoses/fittings. Many older Mopars I've seen since moving down here to Texas have gone the Sanden route, presumably for weight, reliability, and performance. My Hurst is a pretty nice example, but I have it to drive and enjoy, not to look at, so if a non-original Sanden gets me more miles in comfort, I won't mind. I will certainly save all the original bracketry and hoses for some future owner if/when the time comes to pass it along.
