Hot petrol

[Tony Griffiths]

It's interesting that a lot of 1920s American automobiles had a permanent tube, collecting warm air from the exhaust manifold, direct into the carb.
A 1923 Chevrolet I owned- and regret selling, had this feature, and ran like a wristwatch.
You might think this wouldn't work very well, especially when the exhaust got really hot, but it worked fine.

That sounds like a quick, dirty but satisfactory fix for an inlet system that didn't have an efficient hot spot - and far cheaper than tooling up for the production of a new inlet-exhaust manifold system!