Oldsmobile sales soared in the 1970s and 1980s (for an all-time high of 1,066,122 in 1985) based on popular designs, positive reviews from critics and the perceived quality and reliability of the Rocket V8 engine, with the Cutlass series becoming North America's top selling car by 1976. By this time, Olds had displaced Pontiac and Plymouth as the #3 best-selling brand in the U.S. behind Chevrolet and Ford. In the early 1980s, model-year production topped one million units on several occasions, something only Chevrolet and Ford had achieved. The soaring popularity of Oldsmobile vehicles resulted in a major issue in 1977, as demand exceeded production capacity for the Oldsmobile V8, and as a result Oldsmobile quietly began equipping some full size Delta 88 models and the very popular Cutlass/Cutlass Supreme with the Chevrolet 350 engine instead (each division of GM produced its own 350 V8 engine). Many customers were loyal Oldsmobile buyers who specifically wanted the Rocket V8, and did not discover that their vehicle had the Chevrolet engine until they performed maintenance and discovered that purchased parts did not fit. This led to a class-action lawsuit which became a public relations nightmare for GM. Following this debacle, disclaimers stating that "Oldsmobiles are equipped with engines produced by various GM divisions" were tacked onto advertisements and sales literature; all other GM divisions followed suit. In addition, GM quickly stopped associating engines with particular divisions, and to this day all GM engines are produced by "GM Powertrain" (GMPT) and are called GM "Corporate" engines instead of GM "Division" engines. Although it was the popularity of the Oldsmobile division vehicles that prompted this change, declining sales of V8 engines would have made this change inevitable as all but the Chevrolet (and, later, Cadillac's Northstar) versions were eventually dropped.