The GTO became a separate Pontiac model (model number 242) in 1966, instead of being an “option package” on the Tempest LeMans. The entire GM “A” body intermediate line was restyled that year, gaining more curvaceous styling with kicked-up rear fender lines for a “Coke-bottle” look, and a slightly “tunneled” backlight. The tail light featured a louvered cover, only seen on the GTO. Overall length grew only fractionally, to 206.4 in (5,243 mm), still on a 115 in (2,921 mm) wheelbase, while width expanded to 74.4 in (1,890 mm). Rear track increased one inch (2.5 cm). Overall weight remained about the same. The GTO was available as a pillared coupe, a hardtop (without B-pillars), and a convertible. An automotive industry first was a plastic front grille that replaced the pot metal and aluminum versions used in earlier years. New Strato bucket seats were introduced with higher and thinner seat backs and contoured cushions for added comfort and adjustable headrests were introduced as a new option. The instrument panel was redesigned and more integrated than in previous years with the ignition switch moved from the far left of the dash to the right of the steering wheel. Four pod instruments continued, and the GTO’s dash was highlighted by walnut veneer trim.
Engine and carburetor choices remained the same as the previous year, except the Tri-Power option was discontinued mid-model year. A new engine was offered that saw few takers: the XS option consisted of a factory Ram Air set up with a new 744 high lift cam. Approximately 35 factory-installed Ram Air packages are believed to have been built, though 300 dealership-installed Ram Air packages are estimated to have been ordered.
Sales increased to 96,946, the highest production figure for all GTO years. Although Pontiac had strenuously promoted the GTO in advertising as the “GTO Tiger,” it had become known in the youth market as the “goat.”