The First Presidency and Quorum of the Twelve announced this morning that Elder Gordon B. Hinckley has been made a member of the First Presidency [3rd counselor] and that Elder Neal Maxwell has been added to the Quorum of the Twelve in his place. Presumably Elder Hinckley will handle many of the assignments which President [N. Eldon] Tanner has been handling. Apparently they want to retain President Tanner's name as a member of the Presidency. [Hinckly would be referred to as the "acting president of the church" in the press.]
This move will surely be beneficial to our Historical endeavors, particularly because Elder Hinckley is familiar with what we are doing, and because he is positive. He has a positive, favorable view on what we are doing.
[Confessions of a Mormon historian : the diaries of Leonard J. Arrington, 1971-1997, Gary James Bergera, editor, Signature Books, 2018]