for the last two months, almost any time I have driven down a certain street in Bowie, Md., I have found myself interrupting a street hockey game. I also could count on one of the participants, Jimmy Talbert, to shout, "The rangers are going to win the Stanley Cup."

For two months I have been laughing at Jimmy, but the time has come to admit that I, too, am now a believer. The New York Rangers are going to beat the Montreal Canadiens, in the final series opening her Sunday afternoon, and win the Stanley Cup for the first time since 1940.

The Canadiens, striving for a fourth straight Cup, survived a seven-game semifinal with Boston on Yvon Lambert's overtime goal Thursday night. They were lucky to win, since the Bruins were caught with too many men on the ice late in regulation time and Guy Lafleur produced the tying goal on the resulting power play with 74 seconds remaining.

Moreover, in the third period the Canadiens lost defenseman Guy Lapointe, who was wheeled off on a stretcher following a pileup along the boards with Boston's Rick Middleton and Mike Milbury.

Lapointe's injury was first diagnosed as torn ligaments of the left knee. When the knee did not swell up overnight, however, the Canadiens held out hope that it might merely be bruised.

"It's so tender that they haven't been able to examine it yet," Montreal Coach Scotty Bowman said this afternoon. "But since it's not swollen, it may not be serious as we feared."

Even reserving hope for a medical miracle, the Canadiens are not in good shape. They have been struggling with injuries, the defense has been overworked, even with Lapointe, and the club's usual depth has been lacking.So has the Canadiens' usual intensity.

Meanwhile, the Rangers have played like a team possessed of magic, in disposing of Los Angeles, Philadelphia and the New York Islanders, the team that finished ahead of Montreal in the regular season. The Rangers have done it without their leading scorer, Ulf Nilsson, who now has been pronounced fit for service.

If Coach Fred Shero has a problem it would be where to put Nilsson. His team has been operating like a finely tuned machine and there is good reason not to tinker with it.

When the Canadiens play most opponents, they intimidate through statistics as much as power on the ice. Boston, for example, has lost 15 straight games in the Forum and has dropped 14 straight playoff series against Montreal.

The Rangers have no such statistical burden to overcome. They captured the season series from the Canadiens, 3-1, outscored Montreal by 14-7 and won both games in the Forum. Although these teams never have met in a final series, the Rangers have a 6-5 playoff edge and won the last two postseason meetings, in the 1972 and 1974 quarterfinals.

The Rangers flew in tonight brimming with confidence, and Shero said, "I've never seen a team in my life play so well for so long. I think maybe what has helped is we didn't overwork them.

"And I've never seen a team that was so much for each other. Other teams I've been with-the Flyers, better teams that the Flyers-there was bickering, animosity and eventually that kills you. But here they kept together. there are some wonderful people on this team."

The Canadiens were not bickering but several expressed doubts about the club's intensity and physical wellbeing overworked, particularly defensemen Larry Robinson and Serge Savard, who figure to see even more ice time with Lapointe out.

"Intensity, that's basically what it comes down to," Robinson said. "We don't seem to have it any more. I don't mean we've lost our incentive because we've won so much. But sometimes you have to skate a little extra hard when the puck is lying there, or take an extra bump to make a pass. We haven't always had that."

"We aren't the same team we've put on the ice for the last couple of seasons," Savard said."I mean, we've played with injuries all year and it's been tough, very tough. We started the playoffs with a healthy team, but look at us now."

Bowman tabbed Rod Langway to start in Lapointe's place and admitted he had not particularly helped Langway's progress by benching him late in the regular season.

"He played some good hockey for us, but we took him out with a week to go," Bowman said. "We had four games left and a chance to finish first, but it didn't help him. Then we went through the bench in Boston and it didn't pay off. CAPTION: Picture, Montreal Coach Scotty Bowman, left, congratulates Guy Lafleur while other Canadiens celebrate overtime victory over Bruins. Yvon Lambert's goal eliminated Boston in seventh game. UPI