By offering the 1964 GTO as a 389-ci V8 "option package" for the intermediate-sized Tempest LeMans, Pontiac designers managed to bypass the maximum engine size allowed by GM company policy. Their credible street racer proved an overwhelming commercial success and was its own model by 1966.
The "Goat" stands as a classic example of mid-sized American muscle, each iteration bolder than the last, peaking with the 455-ci V8(335-hp) in 1970. But as the muscle car movement faded, so did relevance of the GTO. It was briefly reabsorbed as a trim package for the 1972-1973 LeMans and 1974 Ventura, then discontinued until a just-as-brief revival, from 2004 to 2006.