John M. Lillie, chairman and chief executive officer of Lucky Stores Inc., The California-based supermarket chain acquired last year by Salt Lake-based American Stores, will retire April 30, said J.L. Scott, American Stores vice chairman.

Larry Del Santo, Lucky's president and chief operating officer, was named chairman and chief executive officer of the combined Lucky and Alpha Beta businesses, effective May 1.Scott said Del Santo's first task will be to integrate Alpha Beta into Lucky Stores, a move that was held up for several months by legal challenges by the California attorney general until an appeals court ruling last week cleared the way.

Del Santo, 55, joined Lucky in 1984 and has served as president since 1986 and chief operating officer of Lucky Stores since 1987. Working with Lillie, he engineered the strategic restructuring of Lucky in 1986 and is credited with the success of its food retailing business.

Prior to becoming president and chief operating officer, Del Santo served as executive vice president and prior to that as senior vice president responsible for Lucky's general merchandise, automotive and fabric operations.

He began his retail career with Vons Grocery Co. in Southern California after his graduation from the University of San Francisco in 1957. He progressed to president and chief executive officer in 1973. In 1976, Household International acquired Vons, and Del Santo was appointed senior vice president and later executive vice president of Household Merchandising in Chicago.