HP and Tq Comparison with and without 1969 Mach 1 Shaker Hood Scoop

Late 1960s Ford muscle cars like Mustangs and Torinos were often equipped with shaker hood scoops. These scoops provide fresh air to the engine, thereby increasing power. But as the air enters the scoop it has to bend around the air cleaner assembly in order to enter the carburetor, and we wondered if this would have an effect on horsepower. The graph at the right gives the answer, indicating that in comparison to a straight velocity stack type intake, the shaker costs about 15 horsepower on this engine. Surprisingly, the air filter does not have any significant effect.

However, when the car is running air will be entering the scoop at speed, which can overcome this loss by increasing air pressure at the carb. After these dyno tests, the engine was installed in the car and the car was tested with and without the shaker scoop. At the track, the car was a few hundredths faster with the scoop in place, indicating that the ram-air effect overcame the disadvantage the shaker scoop showed on the dyno.

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