What are you using for mounts? If you are using JohnsCars mounts:
"AC compressor mount and drive: New aluminum high efficiency compressor, made in Japan (serpentine belt drive). I do not supply or make the hoses except for factory air conditioned cars as there are too many variations. Most hydraulic hose or AC shops can make you a set when you drive the car to them. The GM factory AC compressor will not clear my mounts so I designed a custom unit. My package includes all mounting brackets and hardware, uses stock GM belt ,freight paid - $450.00. Hose set, drier, pressure switch for "280" models with factory air is now available, $200.00 (only with my A/C kit)."
If you are using custom mounts im sure you could use a stock bracket.