Allen, who was among three players tied for first after Friday's opening round, is at 10-under 134 after 36 holes. Jay Don Blake and John Cook each shot 5-under 67 Saturday and are tied for second at 9-under for the tournament.
David Peoples, who was tied for first after the opening round, shot 2-under 70 Saturday and is tied with Mark O'Meara (69 Saturday) for fourth. Friday's third co-leader was Mark Calcavecchia, whose even-par 72 Saturday dropped him into a tie for ninth at 6-under with one round to play.
Birdies at the first and fifth holes Saturday had Allen still tied with Peoples and Calcavecchia for the lead before he dropped in a 20-footer for birdie at No. 8 to take sole possession of first.
He added birdies at 10 and 14 but ended up in a fairway bunker on the par-5 15th hole and settled for bogey there. Three pars the rest of the way finished his 68.
Charlize Theron not engaged to Sean Penn 'yet'
Pistorius testifies he didn't consciously pull trigger when he shot girlfriend