I had a set that were hand picked off the line by a racer that he claimed were top notch. Ran them for a season in my boat and when I went to sell them the buyer insisted on a dyno test. Shipped them to Joey Griffin and he said they tested out around 555 - the best set he'd every dynoed. I guess they can vary greatly.
Agree here, the Blue motors are rated at the prop shaft so the "on the dyno numbers" seem to be in this range to make the 525 @ the prop. Anyone that claims 600 out of their 525's is smokin' some real good chit.