how to change the water pump on 2000 Ford F-150

I am replacing the head gaskets and I AM HAVING problems taking out the water pump

Asked by for the 2000 Ford F-150
if you look at the new pump, there is a shoulder that goes into the block.
when removing, especially when it is old, you have to soak it in blaster and then gently pry out a little at a time evenly around the pump. clean off the surface before installing the new one.