Almost done with a rough swap but lost in hoses....

I got this running:  2002 Expedition 5.4L Windsor Engine, going in a '97 F-150 4x4 which had a 4.6L Romeo engine. I got everything in except the electric cooling fans, and connect the battery. Now, I started filling up the radiator and I got a leak on the back side of the engine. I have isolated the leak to what looks to be a line coming off the main water pump line from the back of the engine. My problem is that I do not know exactly what connects back to that line. There is a line in the center of the intake on the front that was plugged into where the PCV valve lines go. I do not just want to plug this line in and try to drive it. I want to make sure before I pull out of the driveway that these lines are right.  My 4.6 did not have this line, so I am lost.