Bracket racing is dull for spectators. Heads up racing is exciting for spectators. So, IMO, a spectator event like heads up classes, should be funded by the spectators and sponsors, not the entry fees of the racers. ie a payout to many of the contestants, so they don't have to have the fastest car to win some money.

Bracket racing purses are paid from the entry fees. It is by the racers, for the racers. That is another reason there are more bracket race cars than heads up cars.

I like the attempt to make Muscle Street an entry level (lower cost) heads up class. But they seem to be having problems attacting racers, so they open up the rules. The simplest thing would be to limit heads to factory production cast iron offerings, that will keep the cost down. The guys with aftermarket race heads can enter the other classes. I bet if they paid more than the entry fee for the 16th place car, they would have at least 16 cars! Same for 32, etc. How many cars do you want? Just pay them from the spectator gate fees, it is suppose to draw spectators, right?