Thats great to hear Mike, I think this needs to be done. It should probably be split into a couple of groups, ie, original cars that raced prior to (for example) 1973, and cars that raced after this right through the the late 1980s Sports Sedan era. Slick tyres began appearing around 1973 (ish) on tin tops, and many cars from this period onwards were built around slicks. And you wouldn't want to have the Sidchrome Imp in the same race as Roger Williams Greenwood Corvette etc.