I never put much stock in the numbers off our local wheel dyno...but they are a great tuning tool. If you can can find 40 horsepower they are worth the time and effort, doesn't really matter what the actual numbers are. The popular local shop uses a "half correction" factor (to sealevel).?!

All I know is, there are an aweful lot of 500+ horsepower cars that come off that dyno that only run 12s at the dragstrip. Since my engine only made 430 on the dyno it should read less at the wheels, but running 11.50s it would probably show over 600 on that dyno!