The first evolution of the First Generation Ford Mustang was available for the 1965 and 1966 model years. Although launched in March of 1964, the Mustang was officially considered a 1965 offering. Early Mustangs are commonly referred to as "1964-1/2" models, while cars built after August 1964 (the standard start for 1965 production) are referred to as "late 1965" cars. For the first months of Mustang production (1964-1/2), only a hardtop coupe or convertible body style was offered, but when the full 1965 Mustang began production, a fastback coupe body style was added. These body styles were offered in Base Model or GT trim, with a range of inline six and V8 engines, as well as manual and automatic transmission options. Due to the popularity of the 1965-1966 Mustang, it is common to find them converted to Race Cars, as well as Custom cars that feature a wide range of modifications. Some of the most notable Mustang variants for this era were the Mustang A/FX, which was a limited run of 15 factory cars converted for Factory Experimental drag racing, and the Indianapolis Pace Car Edition. The 1965-1966 Ford Mustang was replaced by the 1967-1968 Ford Mustang.