Dave, I posted this last night on our Harley board, the same principles apply. It doesn't answer your question completely, but hopefully, it's food for thought.

EFI and carbs are different animals on an engine, the fuel flow characteristics are different. The Carb requires air passing thru it to draw fuel out of the carb then into the intake ports, the EFI shoots fuel directly from the injectors into the intake tract near the entrance to the head at precise intervals, fuel doesn't have to flow completely thru the intake manifold like in a carb set-up. The butterfly on the EFI unit only controls the amount of air entering the engine, the carb butterfly controls both air and fuel flow entering the engine.


Mike