Carter AVS on a 340 drains of fuel

A lot of the problem is the fuel they us today evaporates a lot worse than the fuel they used in the late 60 early 70. ( modern efi doesent need evap protection like regular carb, electric pumps ) you can try a good insulated spacer under you carb, it seems the carters are worst than holleys, or demon, ( The the fuel bowls are not directly on the hot intake like a carter.