a problem with those runs. But like you said, everyone else' car that day had numbers that appeared to be normal. Go figure. The 512hp result was up at XX Tuning on their dynapack dyno, and I'm told those can measure a bit low sometimes compared to a Mustang dyno.
Last dyno w/sport 600's 512 whp 470 lbs-tq On 93 octane @ 17psi