I'd go with an aftermarket system, and avoid the York compressor altogether. The York uses twin pistons to compress the freon, and hence is rather "heavy" on the engine when it kicks in. Newer compressors utilize rotary compressing units which are more efficient and puts less strain on the engine. I had my 74 144's compressor replaced with a Sanden unit (after 28 years!)with some modification to the mounting bracket. Works just as well, but a little easier on the engine. You can reuse the plumbing if it came with the system out of the 72 that you have now. You might also want to consider switching to R-134 refrigerant due to the high cost of the R-12 as well as being more environmental friendly.
PS: During its heyday, the York compressor used to produce frost in my A/C vents!...brrrrr!