Mary Revak Dacko;78;formerly of Rostraver Township;died Thursday;Aug.23;1990;in Canonsburg Hospital. She was born Oct.8;1911;in Donora;a daughter of the late Conrad and Cecelia Krowich Revak. A lifelong resident of the Mon Valley;Mrs.Dacko was a former member of the Mon Valley Art Club. Mrs.Dacko was preceded in death by her husband;Charles Dacko;her sister;Anne Duncan;and a brother;John Revak. She is survived by two daughters;Cecelia Pysh and Melanie Cooper;both of Carnegie;one brother;Dan Revak of Parma;Ohio;six grandchildren and one great-grandchild. Friends will be received at the Vladimir S.Corba Funeral Home;300 East Main St.;Carnegie;Saturday from 1 to 5 and 7 to 9 p.m. and Sunday from 11 a.m. to 5 p.m. Chapel services will be held at the Belle Vernon Cemetery Monday at 12 noon with Rev.Tom R.Smith of Washington officiating. The Valdimir S.Corba Funeral Home is in charge of arrangements.