[TimG]

1973 is the cut off for a true vintage race car as things started to get really radical at that time. A car with history prior to 1973 is vintage eligible in all venues and cars with later history or cars that have been built to vintage race standards can race in many venues.
I raced a 1968 Z28 at Road America in 2004 and this car was built from a roller in the 80's. Certainly no vintage race history, but built to conform with the rules. Many if not most of the cars that raced last weekend at Texas World Speedway for the CVAR event never saw a race track in the 60's or 70's. The Monterey Historics only allow cars with proven race history, no currently built stuff at Laguna Seca.