According to an informal poll today, 76 of the 77 entrants in the 41st Masters golf tournment starting Thursday over the Augusta National Golf Club course think they can win. The lone exception is slump-ridden Johnny Miller, who said: "I don't expectr to win here and neither does anybody else."

Ray Floyd, who surprised everybody last year by leading the Masters from first round to last, registering 17-under-par 271 to tie Jack Nicklaus for the tournament record, was confident he could repeat. nicklaus, a five-time winner of the tournament who again is favored, is the only man ever to win consecutive title here - in 1965 and 1966.

The field of 77 includes 55 U.S. pros, 14 foreign pros and eight amateurs.Lee Elder, Washington's representative on the tour, is getting his second crack at the Masters. he became the first black to earn his way in 1975 but failed to make the cut with a score of 152 for 36 holes. This time, he vows, he'll do better. Vinnie Giles of Richmond, former U.S. and British amateur champion, is among the eight amateurs facing the cream of the pro crop.

Tom Weiskopf, the moody Ohioian who has been a runner-up in this tournament four times, is regarded as the dark-horse favorite. The 34-year-old Weiskopf has been playing well in practice rounds at Augusta.

"I'm hitting the ball well," Weiskopf agreed today. "The past four years, I've played well in practice and finished tied for second in two of them. The difference is around the greens. Scoring is simple. If you can hit the ball close to the cup, you can score. I have always said that some day I'd win this tournament. Everybody wants to win the masters. The rewards and prestige are far greater than winning a regular tour event."

Weiskopf has a temper but he insists that he gets angry with himself and not with the press. "I never considered myself a bad guy," he says, "I'm a perfectionist and ask a lot of myself when I'm playing good, I'm Tom Terrific." Floyd adhered to the thesis that the so-called "young" players will not win. "I don't mean a young guy like Ben Crenshaw, who is 24," said Floyd. "I mean a young guy has to have the Masters experience which many of these tour winners playing here for the first or second time don't have. The Masters is not a putting contest. Good shots are rewarded. I'm playing well and I like my own chances."

Miller has had a miserable year, He has played in eight tournaments, has missed the cut three times and has withdrawn three other times because of a sore left wrist and left shoulder. He has earned only $1,173 this year.

"I'm only 29," Miller said, "and I don't think I'm washed up. People say - and it's not true - I don't care any more about winning since I accomplished my original goals of making $1 million and winning at least one major title. I've won two majors - the 1973 U.S. Open and last year's British Open.

"I know I'm in a slump. It happens to everybody. Since nobody, including me, expects anything, maybe I'll go out there and rip the course. I've paid the price. I've studied films and have gone to other pros for help. But I think my game is coming around."

Tom Watson, 27, former British Open champion and the current leading money-winner with $135,185, is another contender. Watson won the Crosby and San Diego tournaments, back to back, this past winter. He then lost fourth-round leads in both the Tournament Players Championship and the Heritage Classic. He was also leading the 1974 U.S. Open the last day and blew to a 79. "I guess," he observed today, "I'm going to have to prove to you guys (the press) and to myself that I can hold up under pressure."

Nicklaus followed his usual format for the Masters by playing two rounds last week, returning to his Florida home, and then coming back to Augusta Tuesday for more practice.

"I felt I was playing well last week," he said, "but this isn't last week. The winds were a problem the last two days and this course could be tough if we get the same kind of weather for the tournament. This course requires hitting the ball quail-high with a soft touch. I feel like I'm playing all right and am looking forward to the tournament. I never fail to get a thrill out of coming to Augusta.

"As for the young players, what is considered young? I won the Masters at 23. That was young. Let me just say that any young guy will be a factor if he plays well."

The cut will be the low 44 players and those within 10 shots of the leading score.