Converting to 134 requires a bit work to do it properly. Replacement of o-rings with a different material, changing to a different type of oil, etc. Here's a couple of sites that should have more info...I would also say that the old RV2 A/C compressor runs much better on R-12 and would pay the extra money to have it filled with re-cycled or new R12.RockWannabe77 said:Definitely do not put 10W-30 in it. I'm not sure myself but I've heard that the 70's chrysler A/C compressor doesn't convert well to R-134 (supposedly the 134 destroys O-rings or something) anyone else have info on that?