I cant answer all your questions but can add a little. The 4gc wasnt a bad carb one of their bad points was the gas didnt circulate thru the secondary bowls. They filled up and if you didnt use the 4 bbl the same gas set there forever. Ive seen some varnished messes on some of them. The heat tube from the choke went to a "stove" in the exhaust manifold.
