I got one of the aluminum 440 source housings to put on the 440. I will need to replace the heater core in the car later on down the road when i get more time. On the factory housing i had 2 pipe plus in the heater hose outlet holes. On this aluminum housing, one of the holes is bigger and im having a hard time finding the right pipe plug to screw in it. I found one that is 1/2 but the threads dont go all the way up so the head bottoms out on the housing and just starts digging into the aluminum when tightening it..I need the type that gets tight when there is still thread showing. The smaller hole is fine as its the same smaller size as the original housing and the pipe plug works fine in it.