Pulleys Required for AC

[70 Challenger Lover]

On my 70 Challenger with its original 383, the car did not come with power steering or AC. I want to add both. It's going to be aftermarket Vintage Air. Do I need a three groove crank pulley? And will the single groove water pump pulley be used or do I need something different?

[anlauto]

I think you need to wait and see what compressor you're using...If it's a single belt or double foe starters 

[70 Challenger Lover]

Makes sense. Am I correct in assuming the belt on the alternator and water pump remain the same and fill one crank groove? Then PS would be another crank pulley groove? And then the AC compressor (whether one or two groove) is a direct drive off the crank pulley?