Well just another thought....I made a plate out of AL to cover thermostat housing and drilled and tapped it for a pressure guage. Then used one of the 3/4 npt holes for header water and the other for dump. That was untill I got a Banderlog valve Now I use both 3/4 for dumps.
http://www.hotboatpics.com/pics/data...gauge2-med.JPG
Don............spam in a can