if you are still running a stock mechanical pump you are overpressurizing the carb and forcing raw gas past the neede and seat, flooding the intake with uncontrolled fuel. A reg will not fix this properly, as the backpressure on a stock fuel pump will kill the pump. Put an electric fuel pump on the truck back by the tank after the filter. 4-7 psi pump works well - some say 2.5-4 is better. The flow rate of the pump is more important than the pressure - webers love volume of fuel to work properly.