I just reinstalled all of the under hood A/C parts into my '72 Cuda, using all stock parts. I was told by a few others that the new freon does not work in the older V-style compressors. Sorry to say that they were wrong and the system blows VERY VERY cold with only 2 cans installed. I even used an old dryer (bought off of the ground at last year's Mopar Nats) and after pulling a vacuum and leaving it for 2 days sealed, it worked perfectly. I still have about 45 Lbs of R-12 but I only use it for my Challenger.
I even used the R-134 with UV dye in it from WalMart and picked up a $1.86 black light bulb there too. Now, I can easily find any future leaks, by looking for any green glow at the joints.
I've converted many late model R-12 cars to R-134 with success before but this is my first mopar V-style compressor.