What was the real horsepower of the Boss 429?

What was the real horsepower of the Boss 429? The Boss 429 engine used a single Holley four-barrel carburetor rated at 735 CFM mounted on an aluminum intake manifold. All these cars had 4-Speed Manual Transmissions and the Boss was rated very conservatively at 375 HP while actual output was believed to be well over 500 horsepower.

The Boss 429 engine used a single Holley four-barrel carburetor rated at 735 CFM mounted on an aluminum intake manifold. All these cars had 4-Speed Manual Transmissions and the Boss was rated very conservatively at 375 HP while actual output was believed to be well over 500 horsepower.