I accidently discovered a serious mistake made by whichever commercial rebuilder performed the rebuild on my RV2 a/c compressor purchased online from a very well known and popular auto parts supplier. Had I not discovered the defect, my compressor would have experienced catastrophic failure involving it's crankshaft and connecting rod bearings. I am passing this on so that others know what to watch out for. I find it probable that there are/were other rebuilt RV2s turned out by the same person who worked on the one eventually purchased by me. As most on this site know, the RV2 compressor was used on Chrysler vehicles with V8 engines from 1964 through 1979 and in truck year through 1980, with only a few minor modifications during all of that time. One mod was that earlier RV2s had a rounded shape oil sump. Another mod had to do with the RV2s internal oiling system. Up through at least 1971 there was a ball and spring installed in a drilled out port in the main body which regulated oil pressure from the pump. That ball, spring, and the drilled out port for their installation was discontinued sometime after 1971. The RV2 on my 1978 Dodge has NO port for a ball and spring oil pressure regulator. My RV2 shop manual for that year does not show one, while the 1971 shop manual clearly shows the ball and spring oil pressure regulator. The bottom line here (and I'll wrap up the rambling shortly) is that I didn't like the rounded shaped oil sump that came installed on my rebuilt unit and in the process of exchanging the round sump for a flat bottomed one from my "carcass pile", I discovered that the body of the rebuilt unit had a port drilled out completely for a ball and spring but was empty! That would have drained oil from the pump directly back down into the oil sump, starving the bearing at the opposite end as well as the connecting rod's bearings. Luckily I was able to scavange a ball and spring from the carcass pile so the only expense that I endured was for a new oil sump gasket. Naturally I got on the phone and ended up with no answers as to why the ball and spring were missing. One rebuilder even said that I was supposed to re use the ones in my old unit which is complete BS because normally the old core is returned for recycling and rebuilding with it's sump intact and sealed against oil leakage during transit. Also having purchased at least 5 rebuilt RV2s from different suppiers in recent years they all come with installed (bolts torqued) oil sumps. One last fact----- Any RV2 will fit any year but IF the main body has the drilled out port for an oil pressure regulator ball and spring then they MUST be installed. The problem is that you can't be sure unless you remove the oil sump and take a look. I sincerely apologize for having used so many words to say so little. I'll work on that!