The Norse took a 21-6 lead after one quarter on two short touchdown runs by Chandler Edwards and one by Brooks.
Kristian Oberlin scored a touchdown for Shelby with a three-yard run.
North Muskegon pulled ahead 35-6 at halftime with two touchdown passes from Mack Young to TJ McKenzie – one covering six yards and other a 30-yard connection.
Brooks broke loose in the second half with touchdown runs of 63 and 20 yards.
Edwards finished with 111 yards on 11 carries and two touchdowns. Young completed 4 of 7 passes for 74 yards and two scores while Jesse Cooke completed 7 of 12 passes.
McKenzie and Brett Huff each had four receptions. Brooks led the Norse defense with 4.5 tackles, Huff had four and kicker Dylan Hoffman converted extra points following every Norse touchdown.
North Muskegon is now 4-2 overall and 3-2 in conference play.