Generally speaking, you can usually find old boxscores in various newspaper archives (Toronto Star, Globe & Mail, NY Times, Washington Post, Chicago Tribune, LA Times), available by individual subscription or free access through your local library, depending on which newspapers they subscribe to.
Here's the Winnipeg-Montreal game summary from both the 14 Feb 1982 Toronto Star and 15 Feb 1982 Globe & Mail editions:
Saturday, 13 February 1982 at Forum (Montreal)
Winnipeg - Montreal 3:7 (0:1, 3:2, 0:4)
FIRST PERIOD:
1. MTL -- Napier 25th (Gainey, Engblom), 16:46
Penalties:
WPG -- Levie (2-minute minor), 6:39
MTL -- Tremblay (2-minute minor), 12:49
SECOND PERIOD:
2. MTL -- Jarvis 16th (Napier, Houle), 2:01
3. WPG -- Steen 9th (Lindstrom), 9:16
4. WPG -- Dupont 9th (Hawerchuk, Watters), 11:59
5. MTL -- Nilan 6th (Hunter, Risebrough), 12:06
6. WPG -- Hawerchuk 31st (Babych), 16:51
Penalty:
MTL -- Picard (2-minute minor), 16:00
THIRD PERIOD:
7. MTL -- Acton 27th (Robinson, Shutt), 2:36
8. MTL -- Shutt 25th (Acton), 2:48
9. MTL -- Shutt 26th (Lafleur, Robinson), 5:45
10. MTL -- Robinson 9th (Jarvis, Risebrough), 9:49
Penalties:
MTL -- Picard (2-minute minor), 7:13
WPG -- Trimper (4-minute double minor), 15:39
MTL -- Houle (2-minute minor), 16:23
WPG -- Watters (2-minute minor), 19:04
MTL -- Hunter (2-minute minor), 19:04
Shots on goal:
Winnipeg (7 + 15 + 11 = 33), Montreal (13 + 13 + 16 = 42)
Goaltenders:
Winnipeg (Soetaert, 60:00, 35 saves, 7 GA)
Montreal (Wamsley, 60:00, 30 saves, 3 GA)
Attendance: 16,422
And here's a slightly different version (variations
in the 3rd period penalties and times) from the 14 Feb 1982 edition of the Washington Post:
Canadiens 7, Jets 3
Winnipeg.....0...3...0.....3
Montreal.....1...2...4.....7
FIRST PERIOD SCORING:
1, Montreal, Napier 25 (Gainey, Engblom), 16:46
PENALTIES:
Levie, Win, 6:39; Tremblay, Mtl, 12:49
SECOND PERIOD SCORING:
2, Montreal, Jarvis 16 (Napier, Houle), 2:01
3, Winnipeg, Steen 9 (Lindstrom), 9:16
4, Winnipeg, Dupont 9 (Hawerchuk, Watters), 11:59
5, Montreal, Nilan 6 (Hunter, Risebrough), 12:06
6, Winnipeg, Hawerchuk 31 (Babych), 16:51
PENALTY:
Picard, Mtl, 16:00
THIRD PERIOD SCORING:
7, Montreal, Acton 27 (Robinson, Shutt), 2:36
8, Montreal, Shutt 25 (Acton), 2:48
9, Montreal, Shutt 26 (Lafleur, Robinson), 5:44
10, Montreal, Robinson 9 (Jarvis, Risebrough), 8:49
PENALTIES:
MacLean, Win, 1:38; Picard, Mtl, 7:13; Trimper, Win, double-minor, 13:28;
Houle, Mtl, 15:23; Watters, Win, 19:04; Houle, Mtl, 19:04.
Shots on goal:
Winnipeg.......7...15...11......33
Montreal......13...13...16......42
Goalies: Winnipeg -- Soetaert. Montreal -- Wamsley.
Attendance -- 16,422
