When lookind for a Masters winner, the rule of thumb is: don't look too hard. Those who win here at Augusta National are either the first famous names that come to mind or else players you'd never guess.

That's why it is worth noting on the eve of the 45th Masters that the two men who shard the all-time scoring record here -- Ray Floyd, the hottest item currently on the PGA tour, and Jack Nicklaus, the best golfer in history -- can barely contain their moods of confidence and enthusiasm.

By contrast, defending-champion Seve Ballesteros and the tour's top dog, Tom Watson, are in moods of such barely disguised disgust that, unless they get some mircle remedial help in the next 24 hours, they leave the distinct impression that they'd just as soon not be here.

The answer to the Masters puzzle is usually either so big and obvious that you overlook it because it's too easy, or else the winning name of time in advance to guess. Seven felllows named Nicklaus, palmer, Player, Snead, Demaret, Hogan and Nelson have collected 22 of the previous 44 green coats. However, when Hall of Farmers aren't in charge here, such marginal golf eminences as Jack marginal golf eminences as Jack Burke, Doug Ford, Art Wall, Bob Goalby, George Archer and Fuzzy Zoeller somehow find a way to become a part of Augusta lore.

To be sure, Floyd and Nicklaus think that the next four balmy days will be theirs to command.

"I feel special . . . have no excuses. I'm prepared. I've never been on a streak that was this long or this good in my whole career," said Floyd, the '76 Masters winner who is the tour's leading money winner ($173,812) this season and the beneficiary of a $250,000 bonus for winning the Doral Open and Tournament Players Championship back to back last month.

"I hope I'm not seeming overconfident because I know what happens to people who are," said Floyd, "but the way I'm playing now, my good shots are within 10 feet of the flagstick and my bad shots are 20 or 30 feet away. I'm going go good that I have to worry about so good that I have to worry about not rushing too much because I'm in such a hurry to get to the next hole and do the same good stuff all over again."

Nicklaus' confidence, after winning two of the last three major tournament that he entered -- the '80 U.S. Open and PGA -- is only slightly less bumptious. The 41-year-old bear waw letting out the sort of rumblings today that he sometimes likes to emit in hopes that smaller animals in his golfing path will step aside. "I'm playing well . . . Actually, I have nothing to work on. All the parts of my game appear to be in working order. I'm fairly relaxed, just a little nervous before the fight, you might say.

"Actually, I'm kind of looking forward to tomorrow. I've rediscovered a couple of things that were hiding from me for the last couple of months. I developed a flaw that was costing me 20 to 30 yards off the tee and, last week, I corrected it. Now, I'm swinging just like I was in the middle of last summer. and, I think that's when I may have played the best of my career.

"My short putting has been acting up badly recently, and I think I've straightened that out, too. I just went back to the piston-type stroke that I used for 20 years and it feels good."

Others coming here in high spirits include Bruce Lietzke and Johnny Miller, who rank Nos. 1 and 2 in Vardon stroke average. Lietzke has a high hook game that many think should prosper here someday, while Miller is so earnest that he has tape-measured the entire course down to the inch. Also delighted to be back among the azaleas are Hale Irin (fourth in money), Tom Kite (sixth) and Hubert Green (in a slump), who are three anomolies at Augusta -- modest hitters who have always had this course wired. Green has finished in the top 10 here six of the last seven years, Irwin five of those seven. Kite has been in the top six in four of the past five years.

Two men with distinguished Masters credentials who either have the blues or else are poor-mouthing the field are Ballesteros and Waston. "Comme ci, comme ca," said Ballesteros, the youngest champion ever here in '80 when he built a 10-shot lead with nine holes to play, then won by four. "I am not as confident as last year. My luck . . . where is it this year? But, who knows, maybe I will play well again. Right now, I am not good, not bad."

Watson, seventh in Vardon and 15th in money, proved he has Ausgusta mastered with his first, second, second finishes from '77 through '79. However, his long game has been absent all spring. Fortunately for Watson, accuracy off the tee is of minimal importance here, as Ballesteros proved last year when, in one round, he hit three wild hooks of the tee into what looked like oblivion, only to end up making three birdies.

Those wishing a more sentimental, but less logical pick, may be charmed once more by the prospect of a Lee Trevino victory. Amidst the wild disagreements among players here over whether the new bent-grass greens here will be faster or slower than last year, one concensus is obvious: the greens will be much softer and, thus, far more receptive to the low, hot Trevino iron shots that he says in the past were "rejected like a skin transplant" by Augusta.

The truth about Augusta National's publinx-like new greens will also be known on Thursday. "Until they get the mowers out, you never know," warned Watson.

"I'm not sure if the scores will be higher or lower this year, although I suspect higher," said Nicklaus. "But I know one thing. This is the last year that anybody has a prayer of beating that 271 (record held by Nicklaus and Floyd). Once these new greens get hard and fast, nobody'll ever get close to that again."