I've never seen any type of control valve that was screwed into the waterpump. You sure about that? There was a temp controlled vacuum switch in the Thermostat housing for the distributor's retard function. This can be done away with as it's not necessary for anything other than smog control.
I am replacing my water pump this weekend. (’70 351c 2v). I bought a new distributor vacuum control valve to install as well.
