As a small manufacturer, Shelby American didn’t observe strict model years, generally making changes only after parts in stock were used up. As a result, there’s no “official” distinction between the 1965 and ’66 GT-350s.
However, the first 262 cars designated as ’66s were actually leftover ’65s retrofitted with the thin-bar grille (also sans “corral”), rear-brake air scoops behind the doors, and Plexiglas windows replacing the roof vents. Subsequent ’66s got slightly softer damping and other suspension tweaks, plus the new options of automatic transmission and the stock fastback’s fold-down rear seat. Paint colors expanded to red, blue, green, and black, all with white stripes.