Grand Am wasn't the first time NASCAR got involved in road racing. They tried to make what was called the Left/Right (LR) series in the mid-1980s with purpose built road racing cars due to a lack of ovals on their national touring series schecule west of the Mississippi River in the 1980s and before the big boom happened.
The series, however, went no where:
https://www.youtube.com/watch?v=kOUjaWYRR0g