The Bruins have played eight Game 7s against the Canadiens, and have gone 3-5 in those games:
1952 Stanley Cup semifinals
Canadiens 3, Bruins 1
After leaving the game with a concussion, Maurice Richard returns in the third period to score the winning goal.
1971 Stanley Cup quarterfinals
Canadiens 4, Bruins 2
Facing elimination in Game 6, Canadiens defenseman J.C. Tremblay scores the winner to force Game 7. Three days later, he scores the winner again, and the Bruins are stoned by rookie goalie Ken Dryden.
1979 Stanley Cup semifinals
Canadiens 5, Bruins 4 (OT)
Too many men on the ice. Given a power play with 2:22 left in regulation, Montreal ties it on a Guy Lafleur goal. Then Yvon Lambert crushes Boston’s heart at 9:53 of OT.
1991 division finals
Bruins 2, Canadiens 1
The Canadiens stave off elimination in Game 6, but fall in Game 7 when Cam Neely beats Patrick Roy on the game-winner.
1994 conference quarterfinals
Bruins 5, Canadiens 3
The Bruins face elimination in Game 6, but win, 3-2, at Montreal. In Game 7 at Boston, Ted Donato and Fred Knipscheer each have a goal and an assist.
2004 conference quarterfinals
Canadiens 2, Bruins 0
The Canadiens win the final three games of the series, sealing it with a Jose Theodore shutout (32 saves) in Game 7.
2008 conference quarterfinals
Canadiens 5, Bruins 0
The Bruins rally from a 3-1 series deficit to force the deciding game, but can’t complete the comeback in Game 7 at Montreal.
2011 conference quarterfinals
Bruins 4, Canadiens 3 (OT)
The Bruins become the first team to win three seventh games in one playoff year, and it begins with a triumph over Montreal at TD Garden. Nathan Horton ends the drama at 5:40 of overtime.