I looked this up just the other day! 2001. We beat Arkansas, LSU and Bama all three in the regular season. Sadly, we then lost to LSU in the SEC Championship game.
Note: prior to 2012, when Mizzou and A&M joined the SEC, the scheduling format was: play the other 5 teams in your division, as well as 3 teams from the other division. From 2012 on, that switched by necessity to 6 and 2.