Where to run return line on 67 Dart?????

On hot days, I can drive the car, get home and shut it down in the driveway. Go back out a little later and crank it and it wants to die. It is trying to vaporlock. I can keep it running and once I get moving all is well. Also it pushes fuel past the needle and seats in the carb. I keep the fuel level half way up the sight glasses. A few hours later, after shutdowm, the bowls will be down to the bottom of the sight glass.