[ddsmith]

I ripped my gas cap apart to cut the spring down some on the relief valve to make it open at a lower pressure. You could cut the spring down to the point that 1/2 psi would open it. If 1/2 psi is overwhelming your floats you've got problems because the pump puts out at least 4-5 psi. Check and see how hot your carb is after running the truck. If you do not have a spacer between the carb and the intake the gas getting into the carb may be boiling out of the bowls.