10.5 will be biggest class... Drivers like..Herrman,Chris Gaytz,"EA"(oh MY),Schreffler,Fairtrace,Johnson,Blackstock,Haynes ,Lessard,Josh H and many many more are not allowed in 17.5. If a driver was in a STOCK A main in past at Major event driver must run 10.5.. That will be a showcase class ......