HO scale is perfect for oval racing !
Not speaking of RRR racers, or resin bodies, in "factory" cars you can find a lot of modern nascar bodies, with real or fantasy sponsors, and even now, some Indycars openwheel cars.
Concerning vintage stock cars, you can also find Xtraction stockers (they released recently a track set containing this kind of cars).
On chassis side, there is room for everyone, from stock TJET to magnet modern racing. I believe there is no chassis without stocker bodies available.
Personaly, for my stocker racing class, for now I'm using old school Life-like bodies on old lighted tomy turbo chassis (slower than the regular tomy turbo). I plan to build a Xtraction racing class, based on the classic stockers Autoworld released recently too (I already have one).
edit : here's also some interesting youtube channels, mainly focused on oval racing (or roadcourse with indycars and stockers).
https://www.youtube.com/user/crashnburnho/videoshttps://www.youtube.com/user/metromike1/videos