I see a number of problems with this idea. The first is that NASCAR would be creating another racing series. Almost every MENCS race already has a Truck, Xfinity or an ARCA support race. How would this series fit in with an already full race weekend?
These cars will attract an already shrinking fan base. The people who drove these cars new are in their 60's, 70's and older. People like me who admired them are in their 40's through 60's. NASCAR already has one of the oldest demographics in sports. This does not help them attract a younger audience.
Lastly, these cars will have to run a spec engine and chassis to keep the racing affordable. The bodies will have to be fiberglass. However, the puritans of the sport will have a field day. NASCAR has run a 100 inch wheelbase since the early 1980's. The 69 through 74 cars ran on a 115 inch wheelbase. On top of the fact that the puritans will complain that Chrysler will not have Hemi's, Ford will not have the 427, etc.
A nice topic to talk about on an internet forum, but very little practicality.