Hi Bruce,
I've had a number of '67-'72 trucks over the years. If I remember your truck should have a quadrajet 4bbl. The automatic choke should work off a small choke stove that is screwed to the intake manifold on the right side with a small machine screw. The actual coil has a metal cover that snaps down over the base and has a hole in the top for the rod to come out and go to choke on carb. If your out looking for used carbs make sure to check the throttle shafts, these carbs are known for wearing out the throttle shafts.