winner before 1975 could very legitimately claim to be the second-best team in the nation
. Even after
the NCAA required teams to choose one tournament or the other, until 1975 only the champion
of each individual conference
was allowed an invitation to the NCAA tournament -- no other team from that conference could go to the NCAAs.
The game that changed all this was the ACC tournament championship game on 9 March 1974. In what many from the area still call "the greatest game ever played", N.C. State beat Maryland 103-100 in overtime at the Greensboro Coliseum for the right to advance to the NCAA tournament. (As the story has it, legendary Maryland coach Lefty Driesell boarded the N.C. State team bus after the game and told the players, "I'm just as proud of you as I would be of my own kids. Now all I want you boys to do is go out there and win the national championship.")
N.C. State did go on to win the NCAA championship that year. Maryland, on the other hand, was so heartbroken by their loss that they declined the NIT invitation, though they were easily one of the top three or four teams in the nation (finishing #4 in the final AP poll). The NCAA field expanded in 1975 to 32 teams, allowing extra teams from power conferences like the ACC to advance, and has since grown larger: first to 48, then 64, and now 65 teams.