Waterneck was stock. Got one from my stash of parts to compare to the one I'm using. The One I'm using is "cast" and the new/old one I pulled out is aluminum. The new one's I.D. is smaller than the thermostat, so it will work as I thought it should. Appears the one I was using "corroded" out around the mating surface, and now is larger than the thermostat. I knew these things corroded, but wow it takes a lot of corrosion to eat away that much material.
