I think my vote might go to the 1985 team with the 1971-72 team right behind.
The 1971-72 team might even have been better. 33 straight wins. 69-13 record. +11.6 average point differential per game. Wilt, Goodrich, Hairston, West, Baylor, McMillan, Riley. West Chamberlain and Baylor were like the current Celtics Big Three with each being 2 years younger than the next one, respectively. Everyone else on the team had like 6 years or less experience. They were one hell of a team.