Yakima has had a "stock car" track here since the 1930's. Here a "stock car" has to have an engine block and body of the same manufacturer. But they are built on tube chassis and not anything I think of as streetable hot road car.
Most would call this a "Modified" division. Depends on the sanctioning body of the racing at any particular track. Some smaller tracks don't use a sanctioning body and just put on their own thing. But there are still "Stock Car" races. Last track I seen it they called the "hobby" class.