R12 ain't cheap - Help me avoid $$$ mistake.

[ssuesens]

So I stopped by my local ''Old School' ac shop this afternoon. He looked over the entire system and said all looked ok. He looked at my rebuilt ac compressor and suggested I swap it out for a 10 piston aluminum A6 style compressor. For $230 he said it would out perform any A6 model with less weight, noise and power draw. He will put in the mineral oil, I will install the compressor, and then he will draw vacuum and fill the system with my R12 Freon. All this for $35. Hopefully I will have cold air by wed or Thurs!