In 1956, Sunoco introduced "custom blending" pumps, an innovation that allowed customers of Sunoco service stations to choose from several octane ratings through a single pump. Sunoco stations offered as many as eight grades of "Custom Blended" gasolines from its "Dial A Grade" pumps ranging from subregular Sunoco 190 to Sunoco 260, the latter a super-premium grade of 102 octane that was advertised as the "highest octane pump gas" and very popular with operators of V8-powered muscle cars of the 1960s.