According to edmunds, the 2005 Ford Mustang is completely redesigned. The Ford Mustang debuted in April of 1964 and became a national sensation. By the late 1960s, the Mustang competed against the AMC Javelin, Chevrolet Camaro, Dodge Challenger, Plymouth Barracuda and Pontiac Firebird. But, like Elvis Presley, the Mustang had evolved from lightweight and simple into overweight and flashy. By the time the oil crisis of 1973 hit, the Mustang had lost its edge in terms of performance and appeal.
Reborn for 1974, the Mustang II rode on a Pinto platform to save development costs and improve fuel economy. Emissions regulations had stifled performance, and the convertible model had disappeared from the lineup. Still, Ford wasn't ready to give up on the Mustang. In 1979, it was completely redesigned. There was even a performance model with a turbocharged 2.3-liter, four-cylinder engine. The new Mustang proved popular, and by 1982, Ford had endowed it with a relatively strong (for the time) V8 engine and the GT designation that continues today.
Download 2005 Ford Mustang Owners Manual