bypassing heater hoses

Here are the pics of my water pump. Orange one is currently on the car and the bare alum water pump shows the threads from an old pump I had laying around. It is a 1/4" pipe thread plug, and I think I was able to just tap the existing hole without drilling bigger, but not positive on that. Just make sure you put some grease on the tap to hold the chips rather than letting them fall into the pump