Great thread. I have the exact same question on my car; '65 Satellite.
What did you do when changing the oil in the '80 OEM compressor - did you just wing it and see what happened? Did you clean out all the old oil, or did ya just drain-and-pour-back-in the new stuff? Did you change the seals anywhere?
Thanks for any more info.
Two years ago I called Classic Auto Air who quoted about $1,200 to take all my stock my hoses, exp.tank, compressor, evaporator, valves, etc. and overhaul them compatible with R134. Not sure what they do to achieve it, but it would be nice to save that money if I can.
- Art