Many of you know who Diego Rosenberg is. He's done a lot of automotive writing for many years. He is also a member of CP and has participated here on occasion.
I found an interesting article that he put online today regarding horsepower ratings. It's a comparison gross vs net from the days when GM basically was only giving us gross HP ratings.
As a young University student in the 70's majoring in Commerce, Finance and Accounting numbers formed a key part of makeup. Cars did too. The Gross vs. Net was a topic that really stick in my craw so I did extensive research on this and found a mathematical relation between the two was in the range of 70% to 80%. In other words you could take a Gross rating and factor it by that percentage to get a decent estimate of Net HP. In doing this I found that the legendary engines of the 60's were not all that more powerful that the Net ratings in the 70's. A quick review of the data in this articles actually substantially bears out my calculations that I have been using for decades to assess HP ratings of engines. I have even written about this on here many times so I am happy to have corroborating evidence posted.
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Ray White, Toronto ON
Formerly - The one and only 1973 LeMans 454 "Astro-Jet"