I've got ERC's brochure here, and there are seven "flavors" of gas listed, including the basic 110K, A8C, and some others. I don't remember just how many of these are at the Salt -- but I'm pretty sure that the racer has a wide selection of fuels available that are legal in gas classes. Rick & Les will help you select one if you're not sure -- and, if I'm right, they'll seal the tank if the fuel they've just put in is legal in a "gas" class and if you ask 'em to seal it.
In other words -- don't forget to ask for a seal if you want to be in a gas class. No seal? No gas class, end of discussion. And -- if you ask 'em to seal it and they've just filled you with alky or nitro -- they won't seal it. Be ready for JD or Dale or someone to draw a sample from your tank if you're in gas class, too.
I'm not sure if the unleaded fuels are all gas-class legal, though I've run their MUL-A and got a record, so that one must be...