The V6 Experiments
Back in the day, in 'Merica, "performance" meant V8, unless you were driving a freakishly expensive Cadillac or Lincoln from the '30s or '40s, in which case it might also mean V12 or V16. If your car ran on a V6, you didn't tell anybody about it and you just hoped they didn't pay too much attention to the engine note.
In 1976 Buick did something a little balsy when asked to make the official Indy 500 pace car. Rather than putting something with a big V8 up there, the engineers showcased a turbocharged V6 instead. While this engine didn't really catch on in the Century, the '76 Indy Pace Car was the genesis of the Grand National's saga.
On America's roads, a related turbocharged V6 was being offered on the Regal.