Bully Dog is running its super mantals, propane, NO2, HX40, their boxes, and who knows what other goodies to get that number. It's an ETC 4x4 and also is at around 475 on #2. The Bully Dog boys are quite impressive individuals, personally. Remind me alot of the Edge boys. Joe D's "Sickly" ran around the 580 hp area with DD2s on #2.
Trucks with the amount of power of these, create VAST amounts of smoke. These high hp readings are "bragging rights", and are hardly usable on the strip, let alone the street with out some way of getting power to the ground.