OK.. was trying to think of a way to make a throttle body that is adaptable to a wider range of displacement. That triggered a memory of the Martin (M&H) carb that used a unique arrangement that offered what is essential a variable Venturi. The original had a complex system of fuel passage to regulate fuel supply but I think it adapts well to having a solenoid stuck on its head. Three parts - solenoid mount/fuel nozzle - Body and rotating "plug" valve. The plug moves up and down using an angles slotted path for its actuating arm.

might be a winter project this year... I don't think it solves the problem of making these for general consumption but I think it looks cool