These carbs are known for being fuel pressure sensitive. If you research, you will find that they recommend you run a pressure regulator set at 5.5 psi or less. Without the pressure regulator when you get on it the pump will increase the pressure. When the pressure gets above 6 psi it bends the float tabs and resets the float height. I have ran into this on nearly every Edelbrock I have seen run. I rebuild mine and will be rebuilding 3 of them this week. They all get a cheap psi regulator now.
It's nice to run the fuel line on the fender away from the heat anyway. Adding a regulator this way will help keep the fuel cooler also.