There is only one compresor for that year and it is the R4 GM compreesor. They are about as cheap as anything made, they work fine with r134a when installed new and using ester oil.
The Sanden compressor is a good alternative for diesels up to 1978 with York two cylinder compressors. These compressors are not suitable to retrofit. The R4 comp is very unusually shaped and mounted which would make it very hard to use anything esle.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician