It is indexed except for the two fastest classes. For instance, the fastest indexed class is a 9.90 class that you can not break out of, or you lose. Races are heads up eliminations and cars can have ANY mods except for autos I believe. Then the next fastest class is anything goes with a 6-speed, which sounds like your class.
its indexed yet still is bracket racing. just not as specific on the dial-in (instead of an actual dial in time you do a category such as 10.50-10.99, etc). and its purely on crossing finish line first (without busting out) in order to win
its been attempted and argued to no avail. too many boneheads with too many varied "opinions" of what a power adder is. it is a good idea though and boggs does have those types of classes for V10 nats racing events IF enough of us show to participate (all motor class, nitrous only class, etc). but, when you get a piss poor showrate like we had in topeka because too many are busy whinning instead of racing, its not done with those "extra" categories, just the brackets.