After only 2 years from the last restyle, the first-generation Mustang was restyled again in 1969. The body was lengthened by almost 4 inches and the entire car became larger and more “rounded.” Quad headlights graced the front of the car. Ford introduced the Mach 1, a performance model akin to the Camaro Z28. Like the Z28, it offered styling in addition to performance enhancements. The Mach 1 featured dual exhausts, special wheels, a removable gas cap, and a matte-black hood with cable and pin latches. The “shaker” hood scoop was an option that earned its named from the fact the scoop actually shook since it was connected to the engine. Another popular option now associated with the Mach 1 were the rear window louvers.

In the middle of 1969, Shelby terminated his agreement with Ford to produce the Shelby Mustang. As such, Ford oversaw the design and production of the GT350 and GT500; Carroll Shelby had little input. The 1969 (and 1970) Shelby Mustangs received more cosmetic changes, with heavily modified front and rear designs. The Shelby Mustangs were 4 inches longer than normal Mustangs.