How many horse power in 420cc?

The horsepower of an engine is not directly determined by its displacement in cubic centimeters (cc) alone, as it also depends on factors like engine design, efficiency, and tuning. However, a rough estimate is that a 420cc engine can produce around 12 to 15 horsepower, depending on its specific configuration and purpose (e.g., lawnmowers, go-karts, or small vehicles). For accurate figures, it's best to refer to the manufacturer's specifications for the specific engine in question.