Heater Hose Question - SB With Short Water Pump

Guys, I'm swapping a 350 into my 64 C10 pickup. I have a short water pump, and all of the associated brackets and pulleys are installed. The only problem I have is with the heater hoses. The truck has two hoses, one 3/4" and one 5/8". The 5/8" hose I have connected to a fitting on the intake manifold, no problem. The 3/4" hose, however, is supposed to go to the water pump as far as I know. The only fitting I can find with a nipple big enough for a 3/4" hose won't screw into the water pump. The threads are right, but the threaded hole in the pump is so close to the casting of the pump that you can only screw in about two threads before the hex portion of the fitting bottoms out against the pump casting. Is there some special sort of fitting required for a short water pump? I feel like I must be missing something.