A taller venturi makes the "intake runner of the engine longer - the distance from the restrictor's "trumpet" or "mouth" to the rotary valve in the crankshaft. Since, the pulse waves that travel through it need more time to do so making tune at a lower rpm setting thus giving better power at low - mid rpm range.

In other words, same as long or short pipe/header.
same as pipe: long(tall) for short tracks, short for long tracks.

Actually, the gasses traveling through the intake runner and exhaust when tuned (when both have the correct length for each other) correctly "think" that both trajectories are equally long, the physical difference being "disguised" by the fluid's temperature.

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