All dynos are different. I've seen 100 hp difference using the same car on two different dynos.

Mine only made 623 hp at the wheels, but ran 9.54 at 140.4 mph at 3800+ lbs.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax