It is not anything pretty. Napa part# BK 6601696, I think is a 5/8 cap, in place of a hose on the water pump goes on with a standard hose clamp. The intake needs a 1/2" npt plug. Most auto parts stores should have them. Ask for a by-pass cap for a waterpump.
Wow, I was not expecting so many replies. I got the part I needed from napa, after giving them a part number the light bulbs turned on, and people realized what I was talking about.
Thanks Alot.