Its too bad your local region decided to limit CAM to only old cars, because your car pretty much as it sits is one of the target markets of the class.
There's no other option where you'll be anything like competitive with your car as it sits, mostly due to tires. Sounds like you'd be legal for SM and CP, but both classes allow you to run race tires (DOT legal in SM, anything in CP). You can swap those on though and be closer to the front.
Note that if there's serious competition, your car just flat out isn't going to be competitive in SM and will only be competitive in CP with quite a bit of modification, most of which results in "no longer streetable".
All that said... If you're new to autox then bring the car out, slap "CP" or "SM" on the side, and have fun. Most folks have at least a year or two of "learn how to autox" regardless of what car they're in before they're competitive anyway so come out, compare yourself to some known local benchmarks (ask around), and have a great time sliding your car around some cones!