Chrysler's factory ratings varied over the years. You'll find claims ranging from roughly 330 hp to over 375 hp depending on the year and configuration. These are *manufacturer's claimed horsepower*, and it's important to note that these figures often differed from dynamometer testing results. Aftermarket modifications could significantly alter the horsepower output in either direction.
To know the *actual* horsepower of a specific 440 Magnum engine, you'd need to have it dyno-tested.
