They conceived of an idea to put a full size car engine in a mid-size car body and sell it to younger, performance oriented drivers. More importantly, they also conceived of a way to slide this idea past the upper management at GM, who had a maximum engine size limit in their mid sized cars. However, a little loophole was found and the car was approved for production, even though the high level managers didn't yet know the car even existed.

Essentially, since the corporate ruling on engine size dictated that the "standard" engine in a mid sized car could not exceed 330 cubic inches, it was decided to merely offer the GTO as an option on the Lemans series. Of course, the heart of the GTO option package was the 389 full size car engine, tuned for performance and dressed up with some chrome goodies. In order to get the car out to the public as soon as possible, DeLorean arranged with many of the Pontiac dealers to take a couple of the new cars, even though they weren't even listed in the official new car descriptive bulletins from the factory. Thus it was that the cars burst onto the scene, and took the motoring public by storm.

In a year or two every car company had followed suit, but no offering matched the combination of the style, performance, and mystique of the GTO. In its relatively short (11 model year) lifespan, the GTO managed to change its shape almost every model year. As a result, there's a GTO for all tastes.

The cars sales peaked in 1966 with just under 100,000 in sales. The car was offered in hardtop and convertible models. The cars desirability slipped drastically from there, so that in 1973, less than five thousand were sold.

As for those three letters, GTO stands literally for (in Italian) Gran Turismo Omologato or Homologated Grand Touring. It was a reference to a European racing class based on production vehicles. At the time Pontiac had a trend of naming their vehicles in this manner: Bonneville, Grand Prix, and LeMans were all from that era.