The winner will be announced Saturday night at a ceremony at the Yale Club in Manhattan.
Dorsey and McGahee have led the defending national champion Hurricanes to an unbeaten record and the nation's No. 1 ranking. The other contenders are Southern California quarterback Carson Palmer, running back Larry Johnson of Penn State, and Iowa quarterback Brad Banks.
"Whatever happens, happens," McGahee said. "I ain't going to get my hopes up high. We'll play it cool."
The closest vote for the Heisman was in 1985, when Bo Jackson of Auburn edged Chuck Long of Iowa by 45 points. With over 900 votes distributed nationwide, the race could come down to how those voters the term "most outstanding player."
Some voters will point to how McGahee and Dorsey have helped defending national champion Miami extend its winning streak to 34 games. They are the first Heisman Trophy finalists from the same school since Ki-Jana Carter and Kerry Collins of Penn State in 1994. Those two finished second and fourth, respectively, in the voting.
Johnson warned that voters need to look beyond the won-loss record.
"I don't care if they vote for me," Johnson told the New York Daily News. "Just look at all the players. "Just because you're on the No. 1 team doesn't mean you're the No. 1 player."
Dorsey was third in last year's voting after guiding the Hurricanes to an unbeaten season. He is halfway there this season, with only the Fiesta Bowl against Ohio State standing in Miami's way.
In improving to 38-1 as a starter, Dorsey has completed 194-of-350 passes for 3,073 yards, with 26 touchdowns and 10 interceptions this season.
"The awards now are people's opinions," Dorsey said. The only opinions that matter to me right now are my teammates and how we do in the Fiesta Bowl (against No. 2 Ohio State)."
McGahee wasn't even supposed to start at tailback this year, but he can become the first sophomore to win the award. He set the school record for touchdowns (27), yards rushing (1,686), total yards (2,036) and 100-yard games (10).
McGahee may have helped himself last Saturday, when he ran 39 times for a career-high 205 yards and a school-record six touchdowns in a win over Big East rival Virginia Tech.
Having two candidates from the same team undoubtedly could split votes. Nebraska's Mike Rozier is the last player to win the Heisman Trophy and have a teammate finish in the top five in voting. He did it in 1983, with Turner Gill finishing fourth.
Palmer, a senior finally living up to expectations, is trying to become the first Heisman winner from a West Coast school since USC's Marcus Allen in 1981. He has completed nearly 63 percent of his passes for 3,639 yards with 32 scoring passes and 10 interceptions this season.
He finished the regular season with 425 yards passing, the most ever allowed by Notre Dame, and four scores in a 44-13 rout. He will lead the fifth-ranked Trojans into the Orange Bowl against Iowa.
Johnson became only the ninth player in Division I-A history to rush for 2,000 yards in a season, amassing 2,015. He has added 341 yards receiving, a school record for running backs, and 2,575 all-purpose yards, the ninth-best total in NCAA history.
The case against Johnson is that he ran for fewer than 80 yards in losses to Iowa, Michigan and Ohio State.
History indicates that 2,000 yards gets you a Heisman Trophy if you play for an elite school such as Penn State. Rozier, USC's Marcus Allen, Colorado's Rashaan Salaam and Texas' Ricky Williams all gained 2,000 yards and took home a Heisman., but LaDainian Tomlinson of TCU and Texas Tech's Byron Hanspard each rushed for 2,000 yards once, and Iowa State' Troy Davis did it twice and failed to win the award. Barry Sanders won a Heisman at Oklahoma State, but had to gain over 2,600 yards to do it.
On Thursday, Johnson won the Maxwell Award as best all-around player, the Doak Walker Award as top running back, and the Walter Camp Player of the Year Award.
Banks is the sleeper of the five, having come from nowhere to lead No. 3 Iowa to its first 11-win season and a berth in the Orange Bowl after never starting a Division I-A game. The senior from Florida has completed 155-of-258 passes for 2,369 yards,with 25 scores and four interceptions. He also has ran for 387 yards and five scores.
One his best performances came in a 42-35 overtime win over Johnson and Penn State, when he threw the game-winning pass in the extra session.
Last year's race also was tight as Eric Crouch of Nebraska edged Florida's Rex Grossman by 62 points, the fourth-closest ever.