It all depends on what you can re-use from your existing system. If everything else is good, and you only need a compressor, you can buy a re-manufactured YorK (or possibly a Tecumseh) for about $250. If you also need a clutch, pretty well double that. A Sanden-type with a good mount adapter will usually be in the range of $200. Remember, the A/C part of the ventilation is just a small box housing the evaporator behind the chrome vents above the radio. Unlike present day units, none of the heater/defroster ducts and plenums are used except for the part that brings the fresh air in on the passenger side. You don't need a big, high end compressor for this small system.
Next to consider are the hoses. If they are still good, they'll work with either compressor, but I'm not sure if there are adapters available to go from the original fittings to a Sanden-type compressor. Likewise with the evaporator and thermostat. If it's good, it doesn't matter which compressor is connected to it.
In my case, I'd had it with trying to make the old compressors work and decided to go with a new Sanden-type. My intention was to replace the hoses in the engine bay back to as close to the firewall as I could go because I didn't want to get into pulling the dash to get to the evaporator connections. I bought a kit with the compressor, dryer, hoses and all necessary fittings. I also bought a Mastercool crimping kit.
I was going to do all the replacement myself and then take it to my regular mechanic to get it evacuated and charged. After looking at it, he convinced me that the existing hoses were probably ok, the argument that 134-A will pass through the hoses is generally a red herring, and he would prefer to do all the work so he was sure of how it was done. His plan was to only cut the existing hoses where he had to crimp on new fittings at the compressor.
That's the way I went and it's worked great except for the problems with the controls. But this post has gone more than long enough (sorry), and I will recount my control adventures in another post.
The short of it is, if the hoses, thermostat or evaporator are ok, then either type of compressor will work fine. If there`s anything wrong, then it has to be fixed no matter what compressor you use.
I painted my compressor semi-gloss black before I installed it and it blends in well. It`s quieter, puts less strain on the engine and puts out a ton of cold air. If you`re not going concours, give it some thought.
Sorry for the long post
Terry
64HT (cold)