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The first test we performed utilized the stock intake manifold and throttle body, and the factory charge motion control valves (CMCV). We then installed the CMCV-delete plates for comparison. Despite the relatively high-horsepower nature of the engine, peak horsepower only increased from 409.08 to 410.96, and for the most part, power was left unchanged throughout the pull. In a couple of areas, gains of 2 to 3 hp were shown. For the average street car, they would not seem to be a cost-efficient horsepower upgrade, but on a max-effort naturally aspirated setup, every single horsepower counts.