My '88 N/A 740 recently had its compressor seize up on me right when the heat of summer is encroaching here in NC. I need to replace it, but I have been unable to find any detailed information about the procedure in either the Haynes nor the Chilton books, nor in the Brickboard FAQ. Please let me know any tips or advice you have about things to avoid or things to make sure to do. While I have the system open, I would also like to do a retrofit to R134a and install a variable orifice valve. How would this affect the swap-out of the compressor? Do I need to buy a different kind of compressor for the R134 than I would for the R12? Where are some good (or bad) sources for rebuilt compressors, either on the internet, or in the real world in the central North Carolina area (I'm in the vicinity of Raleigh, Goldsboro, and Fayetteville). Thanks for the help.