The highly successful and versatile version of the Mark IV engine was introduced in 1966 as a production engine option for full-sized Chevrolets and Corvettes. The bore was increased to , with power ratings varying widely depending on the application. There were smooth running versions with hydraulic lifters suitable for powering the family station wagon, as well as rough-idling, high-revving solid lifter models usually applied to a minimally equipped, plain-looking, two-door Biscayne sedan fitted with the version of the 427 - (RPO L72).