Otto -
Did you happen to get a heat reading on that manifold after the modification?
The reason I ask is because I am inclined to think that the manifold will get sufficiently warm for the purpose of keeping the carb warm even with the port blocked.
\
It's been a while. The base of the carburetor was getting so hot that the gasoline was boiling in the carburetor. It was 400-500 degrees, if I remember.
Afterward it was much cooler but plenty hot enough for the carburetor to work properly and not boil the fuel out of it.