In the GNCC the current cc limit is 525 cc and the KTM powered machines are 510 cc. So yes you can run the 525 KTM/Outlaw in them. Next year the pro level, Xc1 and Xc2 will be limiting the cc's to 450 cc. So unless your name is Ballance or Borich you can still run the 525 next year to.
Most local series do not have a cc limit on them, but it will be best to check your local racing rules.
2007 Outlaw 525 (#315Q) AC Racing Blackline ProPeg nerfs, Wilson Racing suspension, Precision steering stabilizer, Flexx Bars 15*, Rath Racing anti vib mounts, Rath Racing MX grab bar w/supports, Oury, Pit Posse Outlaw shifter, Vapor computer, JD Jet kit, big O-ring, YFZ throttle mod, Pro design filter, CT Racing full exhaust, RAZR 2, for sand-20x10x10 Edge on Douglas .160.
2007 Predator 500 LE
350 Raptor, 2008 250 Raptor, 2006 Jetmoto 150, 50 Raptor
2007 Outlaw 90(#384M) 2008 Class A 14 and under state champion
2006 Predator 90 (#705M) 10 and under 2nd place in state