The 1979 Mustang was based on the longer Fox platform (initially developed for the 1978 Ford Fairmont and Mercury Zephyr). The interior was restyled to accommodate four people in comfort despite a smaller rear seat. Body styles included a coupé, (notchback), hatchback, and convertible. Available trim levels included L, GL, GLX, LX, GT, Turbo GT (1983–84), SVO (1984–86), Cobra (1979–81; 1993), and Cobra R (1993).
In response to slumping sales and escalating fuel prices during the early 1980s, a new Mustang was in development. It was to be a variant of the Mazda MX-6 assembled at AutoAlliance International in Flat Rock, Michigan. Enthusiasts wrote to Ford objecting to the proposed change to a front-wheel drive, Japanese-designed Mustang without a V8 option. The result was a major facelift of the existing Mustang in 1987, while the MX-6 variant became the 1989 Ford Probe.