I have been on a many year long all but futile quest to finish out my 1968 Atlantic Oil set. Briefly, the cards were issued in 2-card game pieces at gas stations. Forty of them are readily obtained [condition is a huge challenge because the glue from the game piece edging frequently damaged the cards]. Ten of the cards were prize-winners, nearly all of which were presumably redeemed. The grand prize winners--the big money cards--are likely one of ones and long gone.
One other redemption card was issued and it is a lot 'commoner' than others; it got you a booklet of records and stats from the gas station. Not easy but doable; I found one of those:
The cash money prize cards are just about impossible. The only one I've ever seen:
The way it looks to have been cut open suggests it was from a small hoard of unopened packets that surfaced around 20 years ago in So Cal.