318 Can't keep fuel in filter, stalls when hot.

My 67 273 2 brl. did the same thing. Repeating cycle viewed in plastic filter once the engine was hot. Took a while to realize the filter never was actually empty. It was full of vapor. Carb bowl was too. When the needle would open the vapor would go and some liquid fuel would come into the filter.
73 and later have the fuel filter positioned vertically down near the pump and a thicker gasket under the carb. Those changes cured mine. I did find where to buy real gas a short time later. I had enough trouble with fuel lines on the weed wacker, etc.. so everything here with a carburetor now gets real gas.