Originally Posted by trademaster
660whp has to be on a very conservative dyno. They weigh what, 3600-3700 lbs? 139mph trap on 660whp at that weight is fast. Definitely not Dynojet numbers.
There's no such thing as a conservative dyno.
There is however such a thing as a dyno operator that manipulates the factors on his mustang dyno, which can make it say anything.