While the Pontiac GTO would remain a strong seller through the 1960s, its best year came in 1966, rather early in the game.   

As every fan of the muscle car era surely knows, in 1966 the GTO was promoted from an option package to a stand-alone model in the Pontiac lineup. That was more than fitting, as by then the GTO had developed its own distinct image that stood quite apart from the Tempest LeMans on which it was based. Indeed, it was the GTO, none other, that launched the muscle car movement in 1964, creating a hot new sales category for Detroit in the ’60s.

And it was in 1966, too, that the GTO established another sales record of 96,946 cars, nearly hitting the magic 100,000 mark. It had been quite a ride since the introduction: 32,000+ cars in 1964, then 75,000+ in 1965. It looked like the sky might be the limit. But while the GTO would continue to be a strong seller through the ’60s, 1966 proved to be the peak year. The GTO had found its ceiling relatively early in the game.

What happened? In a word, competition. The winning formula devised by Pontiac engineers John DeLorean, Bill Collins, and Russ Gee in ’64—mid-sized platform, big hairy V8, performance and appearance items—was an easy one to duplicate. Most every automaker could assemble their own from their factory parts bins, including the other General Motors divisions. And by ’66-67, the competitors were finding their stride. For Pontiac, the only consolation was that imitation is the sincerest form of flattery.

The list of GTO rivals is too long to name them all here: Ford Fairlane 390 GT and GTA, Mercury Cyclone GT, Plymouth GTX, Dodge Charger and Coronet R/T, Chevy SS396, Oldsmobile 442, Buick Gran Sport. Then in ’68, the Plymouth Road Runner and Dodge Super Bee arrived with their own twist on the muscle car formula. Even little American Motors was eventually compelled to join in with the SC/Rambler and AMC Machine. If nothing else the muscle car category was well populated, with all the variety shoppers could hope for.

Meanwhile, another even larger new sales category had established itself: the pony car, as exemplified in the Ford Mustang. It too inspired a number of imitators, including the Chevrolet Camaro and Pontiac’s own Firebird. While the Mustang and the GTO were remarkably different packages, they attracted many of the same buyers in age and demographics.

A breakdown of the ’66 sales figures provides some insights into GTO buyers. More than 80 percent chose the standard 389 CID V8 with 335 hp rather than the more powerful 360 hp Tri-Power package. (There was also an XS Ram Air package with even greater performance, but fewer than 200 were sold.) Around 37 percent opted for the automatic transmission, a less-than-desirable Super Turbine 300 two-speed, instead of the three-and-four speed manual gearboxes. For a huge majority of GTO buyers, the objective wasn’t really maximum performance. The attraction was style and image, and the GTO had the performance image nailed in ’66.