After having driven the car hard and stopping, the Webers are real cool at the touch.
So it not a problem of the fuel pump or anything else heating up the carburetors. They stay cool just by the air which flow through them.
They only start warming up when I stop the car because of the engine heat accumulating under the bonnet. Stopping the engine still releases a lot of heat inside the engine compartment
Most of the time I open the bonnet and it helps a lot. The phenolic spacers are not of any help in this case. The hot air transmits teh heat to the aluminum,( which conducts heat very easy and fast) of the carburetor body and starts to cook the gasoline inside, which then boils over.
The only way around it is to reduce the fuel level inside the carbs before stopping the engine. Fuel will still boil, but it stay inside the bowl.
This can be done only by turning the electric fuel pump off shortly before stopping or by closing off the fuel supply to or from the mechanical fuel pump.
I removed the intake manifold yesterday in order to get rid of an
oil leak at the rear rail seal, and saw all intake valves sitting in a puddle of a mix of gasoline and
oil. That is no good, so I am taking this route.Since I want to stick to the mechanical pump, a valve to close the fuel supply is the only way to do it.
I am installing the valve and will report my experiences with this modification.