My 49 is all steel. From the tank to fuel pump, from the pump to the fuel filter, from the filter to the carb.
With hard lines from the tank all the way to the carb, I believe that you may be putting some undue stress on the fittings/hardline at the tank and/or the fuel pump due to cab movement (cab mounts) and engine movement (engine mounts). I am sure that it works just fine for you now, but it may be a problem later due to metal fatigue.
