Building a Dirt Track Car

I got the Mopar Performance Chassis book and circle track suspension book. I'll use those the best I can and stay within the track's rules.

I need a roll cage so I should be able to stiffen up the unibody with the cage instead of frame connectors. And the doors need to be welded shut so that should help as well.
In the rules in the body section it says " No bracing of any item allowed." but do you think I could get away with J-bars and claim they are part of the roll cage, or since the tubular asphalt late model stock cars have them I should be able to as well?

With your GM car, would you shift the transmission into different gears, or did you stay in one gear throughout the entire race?