I have a 98 Silverado with a 5.7 vortec. How do I remove the fan from the water pump? Am I going to have to try to hold the water pump pulley still while I turn hex part of the fan?

Take a few rags and hold the blades closer to the center. The bolts should not be to tight once you break em loose.

I usually put a heavy screwdriver between two of the other screws, this becomes the counter force while I am loosening one of the screws, then I work my way around to all of the screws until they are all loose. After that I can remove all screws without holding the others.

I think the question here is how do you hold the pulley still while you loosen the large hex nut holding the fan clutch to it.

they make special tools for it, check the parts stores. I just use heavy screwdriver wedged between 2 of the bolt heads that the pulley on and then use a wrench on the large hex part on the clutch. it will loosen as normal bolt. push the hex part towards the passanger side.