[Hotfingrs]

I always run the regulator after the carb, with a return line. Set the regulator for 7 lbs pressure and the carb will always get that pressure no matter what the driving conditions. With the regulator before the carb, and at WOT, you are limited by the flow the regulator is able to handle. If the regulator can't handle the fuel demand for the engine or carb at WOT, fuel pressure will drop, possibly leaning out the engine. With the regulator after the carb, the carb always gets it's fuel, and the extra is then sent back to the tank.