No, I don't think you do understand....
The SCTA/BNI is not obligated to have a class for race cars from other sanctioning bodies... racing is based on production cars and trucks, roadsters, coupes and 2 special construction categories...
I don't care how many classes there are... as Stan is fond of saying maybe we should have classes for bikes with red seats, black seats and blue seats... and calico if you can't go fast enough in the other classes.
The same holds for all racing organizations, there is a rule book, folks that want to race build cars and bikes to fit in those classes, at least the BNI lets vehicles run if their safety requirements are met, if a vehicle does not qualify for any class, they run Time Only.
No other racing body will let vehicles participate that don't meet their rules, the BNI and USFRA will...
What color is the seat on your bike?