going to hook up a motorcraft 2150 and trying to get the vac routing correct. i have everything in place except for the vacuum for the 4wd. there is a thing on the passenger side fender in the engine compartment. it looks like a ball, and has two vacuum ports on it. i never was sure what this thing was and how you hook it up, if you have to. and the vacuum for the 4x4 should i just tee off of something else? anyone know?