Stuck water pump

[Blue)(Fusion]

I have a new PI intake manifold for a NPI 2000 MGM. I had the old NPI intake off and was on the last step of removing parts. I was trying to remove the water pump to change the NPI nipple to the PI nipple for the new coolant tube.

After trying to wiggle, pry, and ended up hammering on the water pump, it did not budge. I did, however, break my largest screwdriver into pieces trying to pry it out, and started to deform not only the water pump, but the hammer head itself (a brand new hammer too).

Do any of you guys have any suggestions for removing an original water pump on these engines? It had some rust in the coolant when I flushed it out so it may be the corrosion holding it in there? I can not proceed without getting this removed.

Oh, and yes, I did remove the correct 4 bolts, not the timing chain cover.

Thanks!