Stop in for a cup of coffee

The Autocross, is it different classes for different cars. Could I have done it with my Dart ?

Bill
Yes.
The largest sanctioning organization in USA is Sports Car Club of America (SCCA). So their autocross classing is by far the most common, but there others.
It used to be I could explain it in a couple sentences. There were 5 catagories of preparation, and within each, there were a half dozen classes for different types of cars. But now there are so many classes, its easier just to mention the typical options.
Assuming its a v8.
F Street (very close to stock, no R-compound tires)
E Street Prepared (Bolt on modifications, some tire width and diameter restrictions)
C Prepared. (More modifications to engine and suspension, interior, and body work)

'New' Classes
Street Modified.
Classic American Muscle - Traditional (must use tires with at least a 200 Treadware rating)

There may be some "Street Tire" classes our cars fit in too.
A straight 6 Dart might be in slower class than F Street, like H Street.
Otherwise its probably all the same classes as the v8 versions.
Corvairs used to be Nationally competitive in C Prepared, and that's a flat 6 as you know.
At local events, the class competitiveness is always skewed to the local situation. Relatively few people prepare their car to take to compete at National events. Perhaps a slightly larger percentage have skills and practice to drive at the level needed to win those events. Those folks usually kick our butts at local events and give us something to work toward. For a while there were so many top level drivers at our Philly events they got their own indexed class. This way other participants would have a better chance to win the local class trophies.

prob more info than you wanted..LOL