Fill the carb up and get the truck running, then pull the carb off and set in on the bench and watch it for the three or four hours. If it leaks out, tear it apart and find out why. If there is no leak, then the fuel is evaporating out due to heat, a heat spacer can help this. Check the fuel pump for the check valves, your fuel line should never dry out if the pump is good.

Joe

1937 Chevrolet Inline-powered Streetrod