To clarify, you would not have an exhaust leak there, only a vacuum leak. The carb and choke are obviously part of the induction system, not the exhaust.
The area underneath this choke bowl is clearly exhaust related, as it's full of black soot as far as I can see. Plus, when I fired it up with this open, it ran just fine (and it sounds kinda bada-***, for a stock 2-Bbl 318):