It’s no surprise that the average horsepower of a car has changed. When Carl Benz put the first car, as we would recognize it today, on the road, it was estimated to have had 0.75 horsepower.
Henry Ford is credited with saying, “Auto racing began 5 minutes after the second car was built,” which also means the start of the horsepower wars. The horsepower wars got fully underway in the 1950s, though, as car sales started to boom.
That’s where we’ll start looking at average car horsepower, and we’ll be America-centric, but we need to understand something important first. In 1971, the official method for measuring horsepower changed. Before then, it was typically measured with the engine on a block and with no air cleaner assembly, accessories, or exhaust system connected.
Now, horsepower is measured from the wheels of the finished car using a dynamometer. Because a car’s drivetrain absorbs some power (as much as 50 hp), pre-1971 measurements were more generous.