And if you don't snag an entry here on the Forum - you can also hang around the registration area and find someone that's trying to sell his entry. It almost always happens that a few are available then -- didn't finish the car after all, bike motor farted and blew on the dyno - lotsa reasons to sell the entry at the last minute. And the entry isn't specific - no difference 'tween car and bike and truck and so on.
Finally -- while JoAnn, the SCTA secretary, can't sell entries that are not going to be used after all, but she will facilitate the sale/purchase (by you or others) any entries that report to her that they can't use after all. Those are usually sold at a price well below the "late" entry fee.
Don't worry -- you'll get a place to race and probably won't have to pay the late fee. See you on the salt.