Finally broke down and bought an air-gap

Air Gap, good choice. I run one myself. Checkout the manifold shootout Dulcice(?) Steve did in Mopar Muscle a couple years ago. It made within a few hp of the top rated single plane race manifolds with much better numbers everywhere ..exccept above 6500. You will like it. It is tall though so check hood clearance if carb spacer is used. Good luck, Terry.