Allen established a 49-0 lead before the Lions were able to get on the board with a 36-yard touchdown reception by Dalon Willis.
Brian Sutter went 15-for-20 passing for 131 yards and a score. Austin Ludwig led the Lions with 63 receiving yards, while Tyree Johnson led the way on the ground for MHS, totaling 58 yards on 14 carries.
Allen (9-0, 4-0) accumulated 547 total yards of offense Friday night, including 358 rushing yards on 40 attempts.
McKinney (3-6, 0-4) will have one last-chance for a district win as they take on cross-town rival McKinney Boyd (5-4, 3-1) next week at Ron Poe Stadium.