The Southern California-Notre Dame rivalry is different than most. USC and Notre Dame are separated by nearly 2,000 miles and their homes couldn’t be more different. What the two private schools have in common is a history of great teams and great players. No other rivalry game can claim the 22 national championships, with 11 apiece, or the 13 Heisman Trophy winners. While at least one team has been ranked in 64 of the 75 meetings since the Associated Press started the poll in 1936, today’s game ( 4:30 p.m., NBC) marks the third time in the past four years where neither is ranked.