In 1961, Aston Martin debuted the fourth evolution of the DB4 Base Model. Known as the Series IV, this new evolution was mainly offered in coupe body style, although a much rarer Series IV Convertible was also introduced. Although still powered by the established 240hp 3.7L inline six engine, optional triple carburetors became available (only 5 examples are known to have left the factory with this option). For Series IV cars, the previously optional oil cooler became standard, and visible changes included a lowered air scoop on the hood as well as a new barred front grill. Just 185 examples of the Aston Martin DB4 Coupe - Series IV were produced before production shifted onto the new Series V in 1962. Like the Series IV, these new cars were available as a Series V Coupe or a Series V Convertible.