Gas spews out of weber vents but only when car has been run up to operating temp and then shut off for 5 minutes. I get in to re-start it and when the fuel pump is turned on gas spews out of all 4 carbs. Fuel pressure is set at 3.5 lbs. If I tap them with a hammer they stop but some I have to tap more than others. What is causing this ? Why only when hot ? Seems like there is a build-up of pressure in the fuel tanks as well because when I undo the cap there is a pretty substantial hiss. I have yet to try and see if it happens with the tank caps opened before turning on the fuel pump. Any help is appreciated. I'm babysitting this car for a friend and it is a really great car by the way. I really like it a lot. A GT40 with AC. Whoddathunk !