[undy]

and another thing....


Most builders have optimal flowing headers, very free flowing air cleaner (or none at all) and zip point squat accessories when it's on the engine dyno. Now take that same engine, add the average Cobra side pipes, 1 7/8" tall air cleaner and the remaining accessories and your legit 600 hp engine now is 525 HP, engine builder's integrety still intact (somewhat).

The OEMs ( and a few such as Katech, etc) are really the only people who dyno an engine "as installed". This is not a zinger to the engine builders here as there's an infinate amont of installation variables that just can't be accouted for in every dyno instance. That's why a bone stock Z06 typically chassis dynos around 450 RWHP, providing a nominal 11.5% drivetrain power loos and the average "600" HP Cobra loses 20%+ on the chassis dyno.