The Bullets utilized their most spectacular scoring outburts of the season yesterday to overwhelm the Philadelphia 76ers, 121-105, and pull within one game of winning the NBA Eastern Conference championship.

With Elvin Hayes registering 11 of the points, Washington outscored the 76ers, 17-0, late in the second quarter to move from 11 points behind to six head. The Bullets never trailed again.

The Bullets now have a 3-1 lead and have to win only one of the remaining three games to advance to the NBA title round. The series continues Wednesday night in Philadelphia.

"We think we can go up there and win this thing in five," said Bullet center Mitch Kupcheck "There isn't a guy in this dressing room who doesn't feel that way, not after the way we played today."

Kupcheck enjoyed his best game of the series, scoring 19 points to complement 35 from Hayes, 27 by Bob Dandridge and 18 by Kevin Grevey. The club also turned in a solid defensive effort that forced the 76ers to take a horde of outside shots.

But for the 19,035 wildly cheering fans in Caital Centre, the most memorable part of this contest came late in the second quarter.

"We took a page out of the Philly's book," said Washington Coach Dick Motta about the last 4:11 of the opening half. "They destroy people with the kind of streak we ran off. They were shaken, they had to be. They've done it to us enough times in the past for me to know how they had to feel."

The Bullet outburst served as a showcase for Hayes' talents. While scoring 11 of the 17 points, he pulled down five of his game-high 19 rebounds, stole a pass, handed off one assist and dashed around the court like a 22-year-old rookie.

Hayes said he was sitting on the bench, watching his teammates struggles to stay wiht the 76ers early in the second quarter when he decided he had to take command.

"I felt I had to get something going," he said. "I had to assert myself. We had to get the momentum going before things got out of hand."

The 76ers were leading, 48-37, when the Bullets began their run on a layup by Hayes, who was being guarded for the first time in the series by George McGinnis.

Grevey quickly added a jump shot and Hayes took advantage of a MgGinnis turnover with a three-point play off a 16-foot jumper.

The crowd could sense somthing was brewing - and so could Philadelphia Coach Billy Cunningham. He called time out to try to preserve what now was a four-point margin.

But the 76ers had lost their shooting touch. Doug Collins, who had another poor game, missed as outside shot and Grevey fed Hayes with a fine pass for an easy layup.

Hayes then turned in the pivotal play of the game. He stole a Philadelphia pass and dashed the lenght of the court for an enormous stuff shot that rocked the arena and brought the fans to their feet.

Philadelphia was starting to lose its composure. MgGinnis and Dawkins argued in the middle of the floor over how to run a play and Dawkins kicked a chair during a timeout.

Julius Erving tried to provide needed leadership but he missed a jumper and Hayes soared above three 76ers to grab the rebound and muscle McGinnis to the floor. Dandridge completed a fast break at the other end with a 10-feet baseline shot.

Cunningham was trying to calm down his players, but he couldn't get their attention above the roar of the crowd. As he watched helplessly, Henry Bibby tossed a pass into Charles Johonson's hands and the Bullet sub finished a two-on-one break with a one-handed

Another Philly timeout was wasted. The emotion in the Centre over-whelmed the 76ers and they began shooting like a bunch of playground rookies. After two more missed attempts Hayes once again had the ball, to the left of the basket about 12 feet away. He turned and banked in the shot for a 54-48 Bullet lead.

"I didn't want to see it end," said Motta. "We had them on the ropes." But the halftime buzzer sounded and Cunningham tried desperately to regroup his players in the locker room.

"We seemed to lose our confidence in that stretch," said McGinnis. "They crowd got extremely loud was we threw the ball away. They just got great momemtum."

The 76ers challenged during most of the third quarter, once getting to within two points before a three-pointer by Kupchak and a three-pointer by Grevey gave the Bullets breathing room.

Dandridge applied the finishing touch. He had five points near the end of the period and six in a row early in the fourth to push the lead back into double figures.

Moments later, the frenzied gathering went into a victory celebration after a Kupchak stuff and a driving, breakaway stuff shot by 6-foot-1 Larry Wright. "She was watching me on tellead pass from Johnson.

"I know we'll all remember this one. It's great to set up plays, but when we get rolling like we did in that spurt and move the ball like we did, it's the way basketball should be played."

Despite the 17-0 outburst, however, the Bullets had some dreadful moments. Their offense malfunctioned early and they shot just 46 percent in the first half when only Hayes, with 21 points, looked sharp.

But the 76ers were in no condition to take advantage of Washington's lapses. Only McGinnis (24 points) and Erving (22) could score with any consistency, despite Cunninghams' decision to have his team play more deliberately than norman.

"They are going the same way as San Antonio," said Hayes. "They are a running club and now they are trying to set up their plays. Once that happens, you know they are confused."

The Bullets now are oozing with confidence. They have beaten the 76ers twice without center Wes Unseld, who still is sidelined with a sprained ankle. And they have won without playing nearly as well some games as they are capable.

But Motta was not about to start celebrating the end of the series. "It's not over," he said. "It's like an opera. It doesn't end until the fat lady starts singing and that hasn't happened in this one yet."