In the late '90s I raced Wing cars, eventually working my way up to Group 7. Classes at the USRA Nats were Group 7 Pro, Semi-Pro, Geezer, 27, International 15, and Boxstock.
I was out of the hobby for about 20 years, now the classes run at The Nats are very different. What was the timing (and reasoning if possible) for the changes to the current classes? Did Group 7 price and/or technology itself out of existence?