In 1965 Ford launched the Mustang Fastback. The proportions of the Fastback were similar to the coupe and convertible models and many parts including the wheelbase were interchangeable. The fastback featured a sloping, streaming rear roofline. The Fastback was also called the 2+2. This designation refers to the rear interior panel which could either be kept up as a bench seat or folded down flat for additional space. When the seat was folded flat, a hinged trap door could be opened to give a continuous area from rear passenger section to the trunk.
1965 & 1966
The roof on the 1965 and 1966 Fastbacks slopes down and ends about half way into the rear quarter panel. To accommodate the roofline the Fastbacks have a shorter trunk lid and less trunk space than the coupe and convertible cars.
The rear roof pillar incorporated the "silent flow" vent, a triangular cut out that blended with the roofline. The exterior of the vent sported six pillars that look like sharks gills. A control knob inside the car opened and closed the vent.
The 1966 fastback kept the same proportions as its predecessor with only minor cosmetic trim changes.
1967 & 1968
In 1967 the Fastback was restyled. The roofline was extended all the way back to the rear taillight panel and the trunk lid was incorporated into the rear roofline. The car came standard with a rear seat, unlike the earlier models when the fold down version was an extra cost option.
The 1967 Mustang was also larger - two and a half inches wider and a half inch taller. The front grille kept the running pony in the corral, but vertical and horizontal bars removed and the grill opening was enlarged. The side scoops, though non-functional, were redesigned as two smaller scoops with inlets and were painted the same color as the body.