This is only part of the real Story, after Louis Chevrolet left GM, The Chevrolet brothers had there own Aviation Company called Chevrolair, as well as builders of the Frontenac race cars.
In 1929, Louis and his brother Arthur Chevrolet would also form the Chevrolet Brothers Aircraft Company with a new engine of their design but lost the business to Glenn L. Martin.
The Chevrolet "333" Aircraft engine was actually an inverted Dual Over head cam engine that Louis and Van Rast of Duesenberg developed and won the 1920 Indy 500 with Louis' engine called the Frontenac.
During the depression Louis Chevrolet suffered a financial setback and sold the rights to Glen Martin, that later produced the B26 Marauder.
The Glenn L. Martin Company was an American aircraft and aerospace manufacturing company that was founded by the aviation pioneer Glenn L. Martin. The Martin Company produced many important aircraft for the defense of the United States and its allies, especially during World War II and the Cold War. Also, during the 1950s and 60s, the Martin Company moved gradually out of the aircraft industry and into the guided missile, space exploration, and space utilization industries.
In 1961, the Martin Company merged with the American-Marietta Corporation, a large sand and gravel mining company, forming the Martin Marietta Corporation. Then, in 1995, Martin Marietta merged with aerospace giant Lockheed to form the Lockheed Martin Corporation.
see
http://history.gmheritagecenter.com/wiki/index.php/History_of_Louis_Chevrolet
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