This is a CJ5 Dauntless passenger side exhaust riser for the air cleaner. The heat valve no longer works, so I don't care about that! WHAT IS THE approximate 3/8" DIA hole for that is in the second photo? This is on the lower part of the manifold and faces forward. There is a matching hole in the manifold. What is the purpose of this hole? All I find about thermal carb choke support tubing is a 3/16" DIA hole (half the size of existing hole). I ignored this hole with my remanufactured engine install as it seemed moot. Apparently the manifold was plugged <?> I did not remove this exhaust shroud as those two small screws were fragile! Obviously, they broke upon recent removal. Trouble shooting info: I was driving home and upon light acceleration, all of a sudden, I heard a loud HISS. It sounded like a semi truck air brake application...but no big truck around. It was ME! It was clear an exhaust leak was occurring but not just a single cylinder. If there was a manifold plug, it must have fallen out. I'm going on 4+ years of my engine replacement with no other issues. Help me understand what this manifold hole was originally intended! I've stumped the guys over at EarlyCJ5.com. Thanks all!