“Joe you’re right, the carb choke of that type pulls vacuum. Your description is correct.
However, the exhaust manifold isn’t pulling or have vacuum, the carb is pulling vacuum. The exhaust manifold tube simply provides heated air for the carb vacuum.”
I thought that’s what I said. The tube in the hot air stove simply passes through the manifold casting. One end connects to the carb and sees manifold vacuum. The other end is the inlet for that vacuum source. I never said the exhaust manifold was producing vacuum.