Measuring just 2.0 liters and producing up to 305 horsepower, the Hart 420S stormed onto the Formula 2 open-wheel racing scene as one of the lightest 300-horsepower competition engines of its day. The mill reportedly weighed as little as 220 pounds, and its main objective was to remove as much weight as possible, giving whichever car that used it a definitive handling advantage. The Hart 420S was also destined for sports-car racing, giving it a broad scope of potential applications.
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