The early and mid M116 and M117 engines, along with the 6.9 used the Frigidaire A6 compressor for the airconditioning. This was only changed in the final generation models in the W126 to the Nippondenso from 1985.
This would be applicable to cars like the W116 V8s (the sixes used a York), the Series 1 W126 V8, the 107 V8s to 1985 and so on.
The original Frigidaire went out of production in 2024, and there are now a few alternatives you can use.
1) Rebuild your original A6...