Pure conjecture here:
The more I learn, the less I find I know.An issue here would be the pulse would be pulling through the carburetor, but would need to change the direction of the charge in the plenum when the next valve opens up.
The air fuel charge has mass, so as a cylinder pulls from the carburetor, the carburetor flows the mix down and in the direction of the open valve. The mass of the charge continues in that direction, and is reversed when the next cylinder's valve opens. That requires work to be done, and pumping loss in the intake.
As the engine speeds up, it will decrease pressure available to the intake valves. Standing waves could become apparent, which would risk further decrease in efficiency, and fuel drop out and plating in some regions.
CJ
