I think you could find it pretty easy to have a following for all of the early motor classes, 4, 6, 8, V8 etc to be all have to be built only with early equipment, no turbos, no electronics, no specialty heads (other than what was built say pre 1950) and have that in all classes, including streamliners and lakesters. Probably not something that the SCTA would want to get into right now. Even at the price of old speed equipment it would probably be less expensive than some of the stuff you see being ran now.
Rex