If Elvin Hayes and Bob Dandridge opened a crack to lasting basketball fame with their performance in last season's playoffs, then they have the opportunity to swing the door wide this spring.

What better way to be remembered in future years than by being the architects of back-to-back NBA titles for the Washington Bullets in an era when repeat championships are as scarce as bargain gasoline ?

If he can overcome a cold that kept him out of practise yesterday, Dandridge should be much more tuned and primed for these playoffs than he was last year, when he had less opportunity to glide through the final games of the regular season.

All Hayes needed to be ready for postseason play was a few days' rest, which the Bullets granted him this week with a four-day vacation in his hometown of Houston.

"Bobby couldn't play much better than he has recently," said Coach Dick Motta. "The last game of the regular season (against Houston), he put on a performance everyone should cherish.

"He wanted the ball and, when he got it, no one could stop him. You could see him testing his conditioning and his timing. He's an artist out there; you can't describe him any other way."

Hayes prepared for what could be a two-month ordeal of as many as 21 games and three separate rounds by hardly taking a break from any contest. He has a body that demands work to stay in top condition. When he sits out for long periods, he feels uneasy.

"We wanted Elvin to miss the last two or three games," said Motta. "But he wouldn't. He likes to keep playing, I guess maybe because he has only missed five games in his career.

"He played so strongly down the stretch. You have to marvel at him. He really hasn't had an off game since our last West Coast road trip (at the end of February). Now he seems to be playing with the most confidence of his career."

Another year together, along with the emergence of Wes Unseld as an improved scoring threat, has made the Bullet's forwards even more dangerous than last season. They respond to each other's needs on the court better and their movements are more coordinated and more attuned to the flow of the game.

"The longer you play together, the better you should be," said Motta. "But I think Bobby really didn't feel that comfortable with us until the playoffs last year. Then he began doing things like penetrating the lane and dishing off that he hadn't done before.

"Those things became a routine part of his plan for us this season. We learned to use him better and to let him have more freedom when he wanted to go one on one."

Hayes' improvement was in his passing. The quantity of assists was not important. Rather, Motta was pleased to see that Hayes used passes to relieve himeself of the pressure from sagging defenses. The mere threat of his releasing the ball to an open man increases his versatility.

Both Hayes and Dandridge managed to have the most satisfying individual seasons of their lengthly careers and still not detract from the overall club performance. The two have blended their abilities so well in the team concept that Washington enters the playoffs as a far more difficult squad to stop.

Hayes has rebounded and scored and blocked shots so furiously that he is a leading candidate for the league's most-valuable-player award. But Dandridge has increased his individual statistics just as much, so that he also warrants MP consideration. And the two probably will receive a number of votes as an all-league forward tandem.

"They are so good," said Mitch Kupchak, "that each of them can take charge of a game. How many other teams have even one player who can do that? We've got two and I think that gives us an edge."

When Hayes takes command, he calls for the ball in the low post, usually in his favorite spot to the left of the basket, and turns and makes jump shot after jump shot. Or he acts as a rejector in the middle or he runs the court like a sprinter, beating a slow defender to the other end for a dunk.

When Dandridge is in charge, his performance is much more subtle.He will become the lead man on fast breaks or back his man slowly toward the basket before turning for one of those perfectly timed jumpers. Or he will glide across the middle and bang in one of those onehanders that supposedly went out of style with Bob Cousy 15 years ago.

It is nearly impossible to stop the Bullets just by controlling one of these two players. And no club in the NBA so far this season has had a pair of front-court athletes competent enough to handle both of them at the same time.

"That's one reason I came to Washington," said Dandridge. "Instead of knowing they were going to gang up on me, I knew Elvin would have to be covered just as equally. Anybody who wanted to ignore one of us was in trouble."

A review of last year's playoffs shows how effective Dandridge and Hayes can be at peak ability.

The San Antonio series belonged to Dandridge, who not only was unstopable on offense against the weak-guarding Larry Kenon but he also wound up covering George Gervin at the end of tight games.

The confrontation with Philadelphia was a Hayes spectacular. Aroused by the verbal abuse of George McGinnis, Hayes pounded away at the 76ers, starting from the upset victory in the opener when he took command in overtime and refused to allow the Bullets to lose. But Dandridge hardly was silent, as he outplayed Julius Erving and kept the Washington offense geared inside where Motta wanted it.

The two shared honors against Seatle in the championship round. In four of the seven games, they were the first and second-highest scorers. Hayes was also the leading rebounder four times and Dandridge outscored SuperSonic small forward John Johnson, 133-54.

"I don't see any reason why we can't do as well this year," said Hayes. "Who is going to stop Bobby D? And I feel good about my game. I'm relaxed and confident. I want another title. I want it really bad."

Greg Ballard, like Dandridge, is fighting a cold. He worked out briefly yesterday. . . Hayes was kneed in the thigh, which ended the workout prematurely. Motta had hoped to get in a good practice session, but the team scimmaged for only a few minutes. CAPTION: Picture, Elvin Hayes