The major change for 1978 was the division of the rear seat cushion, which had been a single cushion in previous years. A fashion accessory package offered only on coupes consisted of "Fresno cloth" seat inserts, illuminated driver visor vanity mirrors, pockets in the door panels, pin stripes, and other fashion features thought to appeal to female buyers. Seven new colors were also added for 1978.

The Cobra II's graphics got louder in 1978, with "Cobra" in large letters on the door. The Cobra's standard engine was the 2.3L four-cylinder, but more popular choices were the 2.8L V-6 or 5.0L V-8.

For more info on Mustang IIs, check out MustangII.net.