R12 to R134a Conversion

Is your refrigerant R134a? Is it working well for you? If yes, is your compressor A6, R4 or other? Is your condenser stock or a more efficient upgrade? Thank you for your help.
'78 and '79 Impalas my rides.

I have a 77 Impala which I've converted to R134a. I have a stock replacement R4 compressor with stock condenser. I'm happy with the performance (I live in the plains, not the desert). However, from my experience the old stock style R4 and A6 compressors will not hold a charge over the winter in this climate (-20°F). My 72 Chevy pickup with the stock A6 compressor would not hold a charge over winter, either, until I used an aftermarket Rock Auto A6 compressor. I will be trying an aftermarket R4 compressor on my Impala next.

Based on my very bad experience with 134a in my ‘78, I think you are doing very well. Congratulations! I am not smart enough to work on a/c myself, so I rely on local shops. Recently, an aftermarket condenser and a rebuilt A6 compressor were installed. I bought the A6 from a salvage yard in Idaho and had it rebuilt by Classic Auto Air in Tampa, FL. ($565!). The condenser is ACDelco 2170 ($286!). The hi-lo pressure switch, accumulator, orifice tube and hoses are all new. After 17 miles of driving, the compressor and condenser are leaking. The compressor so badly that it is slinging oil onto the underside of my hood. Well, you might say that the shop is obviously at fault. Maybe. However, prior to this compressor, I had two other aftermarket A6s, installed elsewhere, which leaked as well, although not as badly.
Thanks very much for your reply. It will help me sort out what the h… is going on. By the way, I bought the ’78 new, and the a/c performed well for many years with R12.