You're correct Stixx, but my problem is the cases where the dyno 2 dyno numbers are more than 1-2% off . IE Dyno 1 says 480 hp and same engine on Dyno 2 says 520 hp that's almost 8.5% difference. I am not saying that's the case here but if you watch this stuff like a hawk like I do you can find many examples. Always watch the tq/ci figure. There are 3 dyno shops in my area and the one that makes the customer the warmest and fuzziest is the busiest. Hint--It ain't mine. J.Rob