Imagine a piece of exhaust pipe cut in half and placed around header with a tube to connect choke tube to. Held in place with hose clamps. For a neater look, the half with fitting could be welded to header tube. Of course I wouldn't do that with coated headers.
Edit: Of course you could convert to a manual or electric choke if you don't like the looks of this type.
66 Coupe 200ci (Back under restoration)