I have two water pump housings and one is in much better condition than the other due to rust on the inside. My concern is about the bypass ports are not the same size and one is threaded and the small one is not. I think I read that it is good to reduce the size of the port to limit the amount of coolant entering the radiator so more of the cooled coolant goes to the engine. Also is one of the housings for a later car? I'm trying to keep the car as original as I can.