I've tried to float the idea for years that these guys should weld roll cages and put driver's seats inside actual Monte Carlos, Fusions, and Chargers that roll off the assembly lines, and race them every year at the annual All-Star race.
Put racing tires on them, take off the side mirrors, headlights, tail lights, weld the doors shut, etc. whatever you've got to do to make them safe to race.
But use the same V8 engine, body, etc. as the cars we drive on the street. One race a year.
I have another idea for NASCAR, but it would never fly.
The Pennsylvania 500.
NASCAR racing cars travel from one end of Pennsylvania to the other while driving on the Pennsylvania Turnpike. Start at the Ohio border, first one to New Jersey wins. The crazy corners and lower-than-interstate-standard sections would be fun to watch, as well as the 2-3 mountain tunnels. Heck, any sort of NASCAR road race on an actual road rather than a road course would be awesome.