Bring back the 18 speed bicycles that ran at SAS back in the day. Those things are pretty cheap, can pick them up at Walmart for $100. $50 if you catch a good sale. Would probably need to run 30 heat races and who knows how many B mains with all the guys that would show up. Tires would last 10 seasons pumped full of fix-a-flat. Put rattles on the spokes so they sound cool. Just eat your Wheaties and you're good to go. Give larger fellas a head start of a few laps since they're at a disadvantage. Maybe add a tricycle class for the kiddos and a motorized scooter class for gramps.
Seriously, bracket racing? Like index classes? I can hear the announcer now...… "Here comes the 15.00-15.99 second class rolling onto the track. Keep an eye on Fast Frank, he broke out last week and got DQ'ed for running a 14.99!" or "Batten down the hatches folks, here comes the 24.00+ second guys, they tour this 3/8 oval at an astounding top speed of 48 MPH!"