Blake, seeking his first win in a dozen years, completed 36 holes at 8-under 132. His only previous win came at the Shearson Lehman Brothers Open in 1991.
While a number of players were close, nobody could catch Blake, who is just 192nd on the money list this season.
Patrick Sheehan signed for a 5-under 65 and was tied for second with Jerry Kelly and Brett Quigley, who shot 67s. Seven players were another two shots back, including Loren Roberts, a two-time winner of this event.