Exactly. My car weighs 3200 pounds and goes 11.70's @ 114 on street tires, pump swill and full exhaust. What are my dyno numbers? Guess what, never had anyone believe me when I tell them the answer.
Probably not as much as people think... Time slips are all about the optimization of the complete package. Horsepower doesn't mean jack, if the rest of the car isn't optimized to go along with it.
As Moper said, dyno numbers can read whatever the operator wants them to read. Living at 5800' you get all these shops giving guys crazy corrected horsepower numbers. Guys up here thinking they are making a certain number, then go to the track and I'm like, "so what's up with your 600hp car, buddy?" They don't get it, that's the sad part. They still believe they are making the power that some dopey shop told them they were. You can argue until you're blue in the face, show them the math... They don't understand. It's fine, I'll continue to wax their asses with less horsepower than they claim they have... And they will continue to think I'm the idiot LOL.