I think I was in high school when the Pontiac Grand Prix came out. I grew up in Detroit where sports cars were few and far between and the kids in my high school were tuned to whatever the Big Three (and back then there was still the little fourth, AMC) were turning out.
The Pontiac ads that turned my head toward art were those by Van and Fitz, the “Fitz" being Art Fitzpatrick and the “Van “ being Van Kaufman.
What made the Van and Fitz illustrated ads, which represented Pontiac from ’62 to ’70, was the fact that they dared to show American cars in European backgrounds. We had been led, as Americans, by magazines like Road &Track to think American cars were totally inferior to European cars on European turf.
What is almost laughable though, as you look at the early ‘60s ones, is in the drawings, the cars were artificially widened from their proportions in real life or else the people are artificially small (one time walking through a Detroit newspaper photo lab, I realized they used prisms to make cars look longer, lower and wider). Van and Fitz kept up that illusion for a few years