Payne - Cousin

I am looking for information on my Cousin Francis (Frankie) Murphy. Frankie was born in January 1952 to Margaret (Peg) Murphy at Sean Ross Abbey, Co. Tipperary, Ireland. We believe Frankie was adopted by an American couple, Mr & Mrs Henry William Payne. We don't know if they kept the name Francis or if they changed it and unfortunately we don't know any other details. So any information would be greatly appreciated. Thanks, Karen :)