Purtzer had four birdies over the first seven holes and four more on the back nine around consecutive bogeys en route to his lowest round since he opened the Toshiba Senior Classic with a 60.
During the current season, Purtzer has one victory and six top-10 finishes. He is eighth on the money list with $666,495.
Harris had a bogey-free round Friday, playing the back nine in 4-under.
Four others posted 67s, including 64-year-old Rocky Thompson, who claimed the last of his three Champions Tour victories in 1994. He would be the oldest winner on the Champions Tour.