Dyno Vs.Drag Strip Testing

a small block that dynode 400...
at 6000 rpm the fan, water pump, fuel pump, alternator, air cleaner and full exhaust might be 40 hp.
If the dyno is out 10% of 400 that's another 40 hp....now that 400 hp small block might be 320 at the crank and 240 at the rear wheels.
a recent news report said 6% of all accidents are caused by alcohol.That means 94% of the accidents were caused by people who weren't drinking!
You can read the numbers how you like.
It takes me quite awhile to completely tune and get the bugs out of a new build, maybe a few weeks of different driving and weather but i am very fussy.Never been on a dyno...maybe i should?