I think we need to help Ray with some proper terminology about now.
The component that you believe to be a carburetor is called the mixer in basic gaseous fueled systems.
The component that you have identified as VFF 30 is the vacuum operated "Fuel Lock Off Valve", its only function is to make sure that no liquid LPG is fed to the Vaporizer unless engine vacuum is present. That way the fuel system can't fill a building up with propane when the engine is not running.
The component that has 2 coolant hoses, a large hose leading to the mixer, and a small metal pipe coming from the lockoff is the Vaporizer/Regulator.
If the mixer is a CA 100 Impco, it should have that cast into the 4 screw top cover sitting right on top of the mixer.
The Vaporizer should have Model J cast into 1 of its covers.