The Bills delighted a record crowd of 80,235 at Rich Stadium Sunday, beating the Miami Dolphins 24-14, to clinch their third straight AFC East title. Thurman Thomas rushed 30 times for 154 of the team's 206 yards on the ground, including a 13-yard touchdown run, which put the game out of reach early in the fourth quarter. It was Thomas' fifth 100-yard day on the ground this season and 12th of his three-year NFL career, while boosting his 1990 yardage total to a career-high 1,297. The third-year running back regained the NFL rushing lead with 154 yards on 30 carries and scored the Bills' third touchdown on an 11-yard run early in the fourth quarter. Frank Reich, filling in for injured quarterback Jim Kelly, threw touchdown passes to James Lofton and Andre Reed as he completed 15 of 21 passes for 234 yards. The Dolphins running game took a dive, gaining only 35 yards on the ground in 12 attempts. The Bills defense, as usual, put on a great show for the crowd. Marino was sacked three times and had one pass batted down at the line of scrimmage by Darryl Talley. The only sour note occurred when Don Beebe broke his right leg on the final play of the third quarter and will be lost for the season.