The Chevrolet Series AC International is an American vehicle manufactured by Chevrolet in 1929 to replace the 1928 Series AB National. In all, 847,053 Series ACs were manufactured in a range of ten body styles. The Series AC was the first six-cylinder engine from Chevrolet since 1915, and was advertised as "A Six in the price range of the Four", and was only $10 more than the outgoing four-cylinder Series AB (Around $146 today, accounting for inflation). Source - wikipedia