That would be a Northstar engine...try posting in that section.
It is an easy swap in any case but you do need a special tool to remove the water pump cartridge from the housing to replace it. Other than that it is the easiest water pump in the world to replace.
Find the hose coming from the radiator to the engine....the lower radiator hose. The cover that it is attached to is the water pump cover. Remove the 4 bolts and the water pump is underneath. You'll have to take the water pump drive belt off by releasing tension off the small tensioner. Use the special socket to unclock the water pump cover from the housing by turning clockwise....it is a "left handed" cam lock into the casting. Install the new water pump cartridge by turning it counterclockwise and reinstall the cover.
You can find the special socket at most any auto parts store these days. Saw one the other day at Advance Auto for $24 I think. They probably lend or rent them, too.