this picture shows the lines that should connect to a TVS in the water jacket on the manifold. It would normally be with in reach of the lines. As for the EGR if it was stuck open. it will cause a vacuum leek and it will run like crap. Have you pulled the O2 sensor to see what it looks like? These feed back carbs are crap. If you don't have SMOG then I suggest swapping to a Weber. Also try plugging off the PCV valve hose. See how it runs then. Re torque all the intake bolts. Also if you have the box on the fender with 10,000 vacuum lines running in it. They like to crack in there. I'm still concerned about the white smoke being a head gasket. With the radiator full to the top and the cap off. If you start the truck does water shoot out like after a hard night of drinking? Or does it just sit there like a good dog? Also can you get us a overall picture of the engine area, so we can see if there is somthing we might be overlooking.