Today we're going to pick on 1967 and their quaint ideas about what an "economy car" was. Also, we're going to explain a little piece of pop culture slang from the era that may escape some of our more fetal readers.
What kind of numbers would qualify you for economy car status (quotation fingers) in '67? Well, the car was available with as many as six different engines, the smallest of which being a plausibly economical (again with the fingers, please) 2.4 liter four cylinder engine, which made 120 hp / 18 mpg all the way up to the V-8, which returned numbers as low as 11.7 mpg. That's 1967 for you. Now, anyone who wants to burn that much fuel pretty much has to drive a prickmobile or other hilarious prosthetic penis.
In 1967, there was a bit of a thingy going on with the youth culture. Various bands and artists thought they were remaking human civilization as they saw fit. One could proclaim what one liked and disliked by shouting "up with this" and, by comparison, "down with that" (no fingers needed there). Then, because you and your hippie friends were so smart and peaceful, you'd hang around for twenty years and turn into the very thing you hated so much in the summer of love. Well, they didn't call it "the summer of self-awareness" or "the summer of honesty" (do whatever you want with your fingers from now on).
Anyway, Chevy's marketing department chose to strike while the iron was hot and cash in on the catch phrase while it was still in the mouths of the kids they were hoping to sell symbols of the Establishment to. Good job there. The Kids would be ready to turn their backs on their ideals and throw themselves into consumerism, but not for twenty years. For once, advertising got there BEFORE everyone else, instead of chasing the tail of a trend and making an ass of itself.