Stefan.. This is an issue we almost all deal with.. Indeed the gas is boiling in the carburetor and can actually cause vapor lock.
One big help is ilf you can find and use fuel with no alcohol... Makes a big difference... Beyond that you will have to block the cross over in the intake during hot weather.. Perhaps look at an electric pump with increased pressure which may also help some...
Gasoline is a real problem anymore... I know some who put a quart of oil in a full tank of fuel which seems to help! I have the added issues of living at 9200 feet and no alcohol fuels.. Just hope for cool days..
Good luck with it.. Drive that beautiful car..
Ron Husak