Ref: RCR40 & 363sbf.
Do I need the 2 groove pulley on the water pump, or can I run the A/C compressor directly off the crank pulley as mocked up in the attached picture?
I think it is best to drive accessories directly from the crank pulley as in the second picture. If it was an oil pump like in a dry-sump system that would be the way to do it. The on and off loading when the ac clutch is pulled in and out is probably better applied to the crank than the water pump bearing.