[Jamo]

In the San Francisco Region (SFR, Reg. No. 33), we have something called Open Street Prepared (OSP), which is basically a run what ya brung kind of affair. I'm not aware of any other region with it. DOT tires (BFGs, Hoosiers, etc.) are required, and the normal street prepared rules apply, but this is where you find street worthy Chevy powered 240Zs, etc. and Cobra replicas.

Now, there are proper Cobra classifications as well--but it's quite difficult, as you've evidently discovered, to make sure your car actually qualifies. Then there are the prepared classes, requiring full roll cages, etc.

Unfortunately, the folks who run Solo II, now in Topeka, have never really dealt with the situation correctly IMHO.