Gentlemen;
We might be 'off track' here.
The question was about; Water heating the intake manifold on a water cooled 6 Cyl. engine.
When these engines(water cooled)warm up the ambient heat within the engine compartment rises also. As a direct result the carburetor heats too. An engine at +180 degrees F will have an ambient/carb temp over +70F.
Under these circumstances 'carb ice'is rarely a condition or a problem. Especialy in the San Francisco area.
Air cooled aircraft/motorcycle engines are in a different 'ball game'.
Water cooled cast iron V8s use an air duct from the Ex. manifold to the Carb. air intake to address this issue.
Here in So. California these measures are seldom needed.
JM....
