For weeks, it seems, the New York Islanders have had to brush back the tantalizing thought of meeting the Edmonton Oilers in the Stanley Cup final. "Too much to do first," Coach Al Arbour said the other day.

Tonight the Islanders, behind Mike Bossy's record scoring, finished the last of the preliminary work with an 8-4 defeat of Boston, which gave New York the Wales Conference championship and a trip to Alberta Tuesday night for the start of the best-of-seven Stanley Cup series.

"We did really have to work against them (Bruins). They were a good team all year," said Bossy, who scored four goals, including a record-tying three in one period. Bossy also tied the record for most hat tricks in one playoff year at three, tied the playoff record for most goals in a semifinal or quarterfinal series at nine and tied the record for most hat tricks in one series at two.

Boston had displayed a season's worth of intensity in the fifth game of this series on Thursday, beating New York, 5-1, but the Islanders were too determined, too playoff-primed to allow a repeat performance.

After an early 2-0 Islander lead, the Bruins tied tonight's game late in the first period. But after that, New York's command never weakened.

Butch Goring opened the game with a zigzagging race into the Bruins zone that culminated in a goal at the 33-second mark. He started to fake a slap shot, then opted for a more controlled release, sweeping the puck underneath goalie Pete Peeters.

Bossy's first goal came on a power play, when Peeters skated out behind his net to clear the puck away and instead came face to face with Bryan Trottier. As Peeters tried to get the puck away from him, Trottier spun it out toward Bossy, near the crease. Peeters could not get into his net in time to stop the shot.

Rick Middleton turned Ray Bourque's rebound into a goal midway through that period and Craig MacTavish made it 2-2 when he shot the puck waist high at Billy Smith. Smith stretched to grab it, and as he looked in his glove, the red light behind him flashed on at 16:34.

But the Islanders were not interested in ties, even after one period. Bob Bourne went zooming down ice with the puck, flipping it toward Brent Sutter. As Peeters slid to his right to halt it, the puck flew into the left side of his net with four seconds remaining in that period.

"When they had tied us, we knew we had work to do," Sutter said later. "Maybe they were scared, but I know we were playing our best."

Actually the first period was not the Islanders' best--they quickened the pace and raised the standard during the next 20 minutes.

First Bossy, unassisted, charged half the length of Nassau Coliseum, carrying the puck and releasing it high into the netting behind Peeters at 59 seconds.

Bourque got his own unassisted goal four minutes later as he shook himself free of a pesty Gord Lane, took the puck into the corner and out again before smacking it between Smith's legs as the goalie slid on his left side.

But Bossy earned a shower of hats--Mexican, baseball and useless--on his next shot, padding the Islanders' lead to 5-3. Trottier brought the puck around the net and in front of Peeters, where the goalie kicked at it before Bossy poked it past him.

Peeters lost his stick amid a scramble in front of the net, and when the bodies moved away, Bossy had scored again, this time on a rebound of Anders Kallur's attempt.

Trottier's goal came as the wandering Peeters was on his knees, waving his stick at an errant Ken Morrow shot. Trottier simply swept in, lifting the puck into the vacant net in one smooth motion at 13:14.

Middleton's power play goal in the second period gave the Bruins a chance to daydream, but Wayne Merrick's cross-ice feed from Bob Nystrom at 7:41 of the third destroyed the dream and drew a scoreboard message: "On to Edmonton."