Hosepower ratings
OK, there are equations you can use that take your car's real world performance and they figure out what kind of horsepower you're putting out. This equation, of course, assumes that your car is optimized to putting its best performance in the test. Still, it is a pretty good guesstimate.
My race 74 Camaro with its 'baby' big block (396) ran a
[email protected] quarter mile pass. It weighed 3700# with me in it. The equations can be based on elapsed time for the run, or top mph. One method said I had 425 HP, and the other figured out to 460 HP. I average the two and say 440 HP to the rear wheels.
Beta Cat ran
[email protected] At 3850# with me in it, that figures out to between 290 and 340 HP Considering a 'stock' 73 351C-4V was rated at 225 net HP and a earlier 351C-4V was rated at 300
gross HP, I kinda wonder how accurate that is.
Then again, the car manufacturers were playing games with the HP figures for a number of reasons. One was the Insurance industry. The higher the HP rating, the higher your insurance rates. The other reason for the games was for drag racing classification. The higher the HP rating, the more difficult (Faster) classes you had to race against. A good example of the under-rating was the 428-CJ. 335 gross HP? HA! Even the drag racing sanctioning bodies put it much closer to 400HP.
I guess it all boils down to which way you really wanna go with this. You can guesstimate without any real clue, you can get sorta close by taking your car to the track and wailing on it, or you can spend the $$ and have it run on a chassis dynomometer. The choice is yours.