It looks like they are trying to have a class that is all-inclusive, including stock production cars.
The problem is older muscle car are often modified to many different levels. Torque thrusts with wider tires, a bit lower, maybe a set of shocks, and a stronger engine for a start (typical cruise night car), going all the way to a pro-built pro touring car. If you want to run your Aussie Charger, it's NOT American. But they would probably let it run anyway. I haven't kept track of the AMC in your signature, but it's probably not as it rolled out of the factory.

My thought was an extreme example of what is allowed with the minimal rules as stated. It would also be pennies on the dollar compared to buying an older restored car (20K) and setting it up with a decent suspension (5K) light forged wheels and the best tires allowed (another 5K), along with good brakes and an accusump to keep the engine alive (another 1-2K).

Examples of chassis that could be modified for use.


http://www.ebay.com/itm/Modified-Turn-Ke...mtr#ht_44wt_900

http://www.ebay.com/itm/171596919278?for...60#ht_166wt_847

http://www.ebay.com/itm/NASCAR-RACE-CAR-...276#ht_44wt_900

This guy already mounted a vintage body!
3500 is not going to get you much in a 55 chevy OR a muscle Mopar!

http://www.ebay.com/itm/55-Chevy-project...l_#ht_120wt_900


If you look at ebay "SCCA" listings, you will see either real cheap or real expensive. If you just want to run SCCA, you can buy a car done cheap. If you want to get in quick, you can get something like this (I'm sure some Chevy guy who is looking these rules over is also looking at this car)
http://www.ebay.com/itm/251762755065?for...m=#ht_121wt_900

If you want to build a real competitive race car from a 40-year old production car, it is a fool's way to go. Old street tech modified into modern racing is going to cost a huge amount of money and the result is going to be less street worthy and not as good a race car as a modern street car with the same money or a dedicated race car (which they are trying to avoid). This is simply trying to be an all-inclusive class for people with older muscle cars that want to try them out on a race course.

BTW, I know racing beats stuff to death, through running, fixes and modifications. It's not as quick as a demo derby, but it happens. I love seeing old muscle cars out racing, but if that means even more are cut up, rode hard, and dumped out back when the energy or money run out, I'd rather see something like the 55 above or Indy Dave's Aspen Kit Car out there.