I am in the process of replacing mine now 78,000 miles.
I just ordered a water pump from "Diesel Care And Performance Inc" for $109.95 plus $14 shipping. Gasket included with no core charge. I ordered 1 day and got it the next without paying for expedited shipping.
Call this number and ask for Billy Williams: 901-380-9290
You will have to tell him, you are getting the price from their webpage. They sell the same pump on Ebay for $119.
This is part of their ad:
A top quality new production water pump for a 1996-UP 7.3L (466) direct injection Powerstroke engines. This will fit all F250/350/450/550 Super Duty, E150/350, F53/59 Stripped Chassis and Excursion applications. This is one of the best quality water pumps on the market today. Or go to this website:
Powerstroke Water Pump