Senior Tech Team
Join Date: Aug 2002
Location: Alberta, Canada
Re: Old horsepower vs New horsepower rating?
There was a big thing with the insurance companies that if you made more than 1 hp per cubic inch, the costs went up. Which is why you often see power figures that are very close to the cubic inches, but not over.
Another huge difference is gross and net horsepower, net being power with accessories. I think one of the biggest factors, is its just a number rating. Numbers sell.
Despite the belief that the old engines were all these drastically underrated, super monsterous 600 hp engines, they often not nearly as powerful as people believe. Like the Hemi being 500 hp, well I seen a factory dyno sheet on the 426 Hemi, and it made 433 hp, and I think 466 ft-lbs, and I think that was with headers. ZL1 427, ppl think its 600 hp, stock it didnt even come up to 500 hp, after headers (no exhaust), and tuning and stuff, it made 523 hp. 100% bone stock when you put it in the real world, the factory ratings quite a bit off, and they dont make the power as one would expect due to the SAE net standards.