These are all cars I've raced that might fit into your class - all of them pretty stock, non-mag and raced on Sport track.
They are all fun to drive, but nothing matches the Carrera Torino for pure joy. It was a regular in our pairs racing at WHO/digital - and everyone I teamed up with had a broad grin on their face after their stint. I'm pretty sure it never won a race, but it was a top-3 car if driven well. It has Paul Gage 'thanes and some extra weight down low.
The other two Nascars are big and fun. The 20-year-old Pontiac has an inline S-Can and - with the Taurus of the same era - is a cornerstone of our digital racing. Urethanes, a bit of weight and a guide change gives you the potential of a tasty race car that you can really enjoy. The latest Monte Carlo and Thunderbird are good fun too - each having different characteristics, with the Monte more like the 'old' inline Nascars, the T-bird a bit tippy.
We've had pretty much all the Scalextric Trans-Am cars racing at WHO. The '70 Camaro is probably the best, although the '69 model has been a regular in victory lane (including the one pictured) - as has the Javelin, Pioneer '68 Camaro and the Ford BOSS Mustang. The Dodge Challenger and Mercury Cougar don't quite cut the mustard. The Javelin is inline and doesn't feel like a muscle car - it was an error and Scalextric are committed to producing all future Trans-Ams as sidewinders with full interiors.
If you want a sure-fire winner, check if you can run the new-ish IROC-Z Camaro available in red, blue and Duracell liveries. I've seen the red and blue ones new for £30.