I'm about to go onto water pump #4 since I bought this car and I'm considering instead of the cheap cast Gates/Carter pumps an AC Delco 252-629 which is aluminum but I trust their bearings not to fail after a year and a half.
Problem is that the outlet port for the heater core isn't included in the casting. Instead you get a threaded hole. Me, the parts house and every plumbing supply house I've tried so far cannot find a fitting to go from the 5/8" (or something similar) port to the 3/4" hose. How on earth were they expecting you to use this pump with a heater core??