Horsepower

I know in the past a few companies have been in trouble for inflating their horsepower numbers. Can the same also be said for under-reporting them?

In the very early days of passenger automobiles, auto makers in Great Britain often under-reported their horsepower numbers. That’s because car buyers had to pay a tax based on the car’s horsepower rating.

In the mid-late 60s, during the horsepower race among the Detroit Big Three, it is widely acknowledged that Chrysler under-reported the horsepower and torque of their 426 Hemi engines.

Even with under-reporting, the figures were very impressive, to say the least.

Rolls Royce typically does not give the power rating of their car engines other than saying it is “adequate”. This type of understatement actually is a selling point with that level of client.

Yes, The 03-04 Mustang Cobras were underrated from the factory, 1993-2002 GM F-Bodies cars with the LT1 and LS1 were also underated from the factory, the Nissan Titan is also underrated. I don’t think there’s any legal penalty for underrating horsepower figures though.

That was the case 20 years ago, but since VW and BMW bought them out they’ve been giving the HP/torque figures for their cars. Kinda takes away some of the mystique IMO. It used to be either be “adequate” or “exceptional” for their high performance variants.

My parents had a 1964 Series 62 Cadillac sedan. It had the Rocket 429 engine; rated at 375 HP by the factory. But it was generally thought to have more like 425 HP. It was astonishingly quick.

Is there any greater under-reported HP than the L88 Corvettes?

An argument can be made for the Ford 427 SOHC.

“I know in the past a few companies have been in trouble for inflating their horsepower numbers. Can the same also be said for under-reporting them?”

They have never “been in trouble” for doing either…They all do it all the time, if it suits their purpose…Insurance companies start adding surcharges when the horsepower to weight ratio gets radical…