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Here’s the fascinating thing about horsepower ratings: manufacturers test themself and can claim any (provable) number they want. So why in the world would they advertise low numbers? Sometimes they don’t want to outshine their own flagship model. Other times there is a “gentlemen’s agreement” like the understanding that every JDM sports car would advertise 276 horsepower or less–which lasted until 2005. This opens up a prime opportunity for those in the know to really get their money’s worth. Read on to find out exactly how much horsepower these sports cars make.

  • BMW M5 Competition
  • Toyota Supra
  • Ford Mustang Shelby GT350

BMW M5 Competition

Four BMW sports cars race on a track.
2021 BMW M5 Competition | BMW

So BMW is notorious for underrating its own horsepower. This is especially true with its turbocharged engines. Here’s an example: the BMW M5 Competition is officially rated at 617 horsepower at the crank. But independent dyno tests put it at a Hellcat-stomping 700 horsepower at the crankshaft and 617 by the time that gets to the wheels. So you won’t be shocked by its sub-three-second time to 60 mph.

Toyota Supra

Supra in Toyota racing livery rounds a track.
2023 Toyota Supra | Toyota

Motorheads know the new Toyota Supra actually borrows the legendary turbocharged I6 engine from the BMW Z4. Because BMW rated the Z4 at 382 horsepower, Toyota rated the Supra at 382. But then automotive journalists did a dyno run with a 2021 Supra. The result was 388 horsepower at the wheels, 400 at the crank.

Ford Mustang Shelby GT350

A Ford Mustang Shelby GT350 takes a corner.
Mustang Shelby GT350 | Ford

The latest Mustang GT350 will undoubtedly go down in muscle car history. For this special edition, Ford built a 5.2-liter V8 with what’s called a “flat-plane crankshaft.” This configuration, common in exotic supercars, creates an especially high-revving engine. Ford advertised the “Voodoo” V8 with 526 horsepower at 8,000 rpm. But perhaps Ford’s testers weren’t really giving it the beans; independent testers found it makes closer to 581 horsepower at the crankshaft.

Next, find out whether the front engine, RWD car is going extinct, or learn more about why some automakers lie about horsepower in the video below: