Quote:
Originally Posted by Rocky1974
It's interesting, but not very accurate.
GM did build 425 horsepower Camaros in 1969.
All the 67-70 engines were rated in SAE Gross Horsepower.
Since 1972, all engines have been rated in SAE Net Horsepower.
In 1971 all engines were rated in both SAE Gross and Net Horsepower.
SAE Net ratings give much lower numbers than SAE Gross ratings.
As an example the horsepower rating on Z/28 Camaros went from 330 Gross Horsepower in 1971 to 275 Net Horsepower in 1972, with absolutely no changes to the engine.
The end result of this is that a LS3 Camaro is making more than just 1 horsepower more than a 1969 COPO 427 Camaro, a LOT more.
Today's LS3 would be making around 500 horsepower if it were rated in SAE Gross Horsepower.
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Excellent point... but, to counter that true statement (gross hp was basically measured on an engine with no accessories, while net hp is an engine powering the basics, like oil pump, alternator, whatever the engine will actually be powering in a car), back in the 60s and 70s, manufacturers would often claim a lower hp that the actual engine was making (the engine might make 360 hp, but the manufacturer might claim 325 hp). While this seems really backwards to us who love hp and want more of it, back then, manufacturers were afraid of safety regulators (who might cry "foul!" over cars that were "too powerful," and they did not want to scare customers away, those who might be afraid of increased insurance rates for a car that had a lot of horses to offer.
So... the same engine might produce 300 gross hp, but only 270 NET hp (and, there is no direct mathematical conversion, as there are too many variables in each an every engine setup)... but, in order to "underrate" the hp, the manufacturer might have even reported the gross- 300 hp engine at only 250 hp.
Love the OP's chart... I AM going to take from it the fact that my 1LT makes more horses than ANY Camaro manufactured from 1971 through 1997...