[dlampe]

There are also variables on the engine dyno as well. For the best numbers I have seen builders use electric water pumps, carb spacers with the shops carb and stepped headers. There is also parasitic loss due to accessories like water pump and alternator, not to mention the differences in cobra headers and the short little air cleaners we use. This all happens before the drive train loss!

I have always resolved myself to the 17% number but it doesn't matter. What really matters is how much are you able to put to the ground and how fast can that peak power be delivered.