I saw USAC sprints for the first time at Reading, the night before a Champ Car race at Trenton, sometime in the late 50s. I then saw most of those races until the first race at Trenton was won by a rear-engined car. I never went back to Trenton, but I did see a few more sprint races at Reading.

The only IMCA race I ever saw was the last one at the old Tampa Fairgrounds. I don't remember that year either.