The Chevrolet Copper-Cooled Series M was an automobile built only during the 1923 model year. It was made to parallel the Superior Series.
Together with the Superior, the Series M replaced the 490. Instead of having a water cooled engine, the Series M had a radiator grille with louvers, behind which the air-cooled, top-driven four-cylinder engine sat. The engine had a displacement of 2212cc and a power output of 22bhp (16 kW) at 1750rpm. It's cylinder block was made to incorporate cooling fins made of copper. The cars were almost 100kg lighter than their water-cooled counterparts.
There were six different body styles available including a two-seater roadster, a two-seater coupe and a 5-seater sedan, each of these had two doors. More bodies available were four-door variants of a 5-seater tourer in standard and deluxe version and a 5 -seat sedan.
Although the air-cooled cars were lighter than the water-cooled Superior, they were also about $200 more expensive. The sale prices ranged from $710 and $1060. Thus, these models were commercial flop and disappeared without replacement after one year of production. Only 759 cars had been made. In 1923 only 100 units were sold and the rest were rejected in the following years.
Today there are still two cars of this kind still in existence, one of which is in the Henry Ford Museum in Detroit .