why didn't a car manufacturer make a model named the M80? It's clever, and a regional dealership network took advantage of the opportunity, and named a 1980 Malibu the M80 and sold about 1900 in North and South Carolina

At some point in the late 1970s, seven of the most powerful Chevrolet dealers in the southeastern sales zone came up with the idea of rolling up a special version of the Malibu in an attempt to make the fourth generation attractive to a new type of clientele and resuscitate the muscle car enthusiasm of the 1960s and 70s.

It was a dealer package, mostly aimed at the NASCAR fans who traveled to Darlington Raceway in South Carolina 

Front and rear spoilers were also on the menu – the one at the front was from the El Camino SS – while the car rode on 1981 14-inch steel rally wheels from the 1980 Monte Carlo.

https://www.autoevolution.com/news/the-strange-story-of-the-chevrolet-malibu-m80-the-car-that-was-sold-in-only-two-states-248007.html#