70 C10 307 Power Steering Conversion Question (Newbie)

[ChevEE]

I purchase a 1970 C10 with a 307 last week and the previous owner had started to convert to power steering. He had already installed the gear box and made all necessary steering assembly replacements. He told me all that was left was to install the pump, and he provided me with the pump, brackets, and hoses he had already acquired. I was looking through the FAQ's here and found a lot of great information, but there was one thing I can't quite figure out. Is the power steering pump driven off of the crank or the water pump?

I have worked on cars for a long time, but this is my first attempt at a restoration. Any help would be greatly appreciated!