Not since Kareem Abdul-Jabbar began his varsity career at UCLA has an NCAA basketball tournament shaped up quite like this year's.

No. 1-ranked Michigan, Kentucky, UCLA and San Francisco all have support as the tournament favorite, but no team is an overwhelming choice. And the feld is loaded with stumbling blocks that all of these powers will have to overcome before arriving at the Final Four in Atlanta March 26-28.

Thanks to some uneven first-round pairings, half of the 16 opening games Saturday and Sunday are attractive, with some potentially as interesting as any the payoffs will produce.

Here is a look at the best contests:

Purdue vs. North Carolina (East Regional at Raleigh, N.C.) - By the end of the regular season, North Carolina was playing as well as any team in the country, even without injured Tommy LaGarde. But Dean Smith will have trouble pulling the Tar Heels through this game now that Walter Davis also is sidelined.

Smith doesn't have a replacement who posseses anywere near the talent of Davis. He'll have to ask Phil Ford and freshman Mike O'Koren to assume greater scoring loads, but the talents of these two gifted athletes barely were enough to overcome Virginia in the ACC final.

Purdue, which is much stronger than the Cavaliers, is physical enough, with 6-foot-8 Walter Johnson and 7-foot Joe Barry Carroll, to cause the Tar Heels problems in the front court. The Boilermakers have been weaned on the rugged play in the Big 10, where contact between players is tolerated around the basket much more than in the ACC. Purdue already has beaten Providence, Georgetown and Minnesota this year.

However, Purdue's playmaking senior guard Bruce Parkinson sprained his right ankle in practice yesterday. X rays showed no bone breaks, but the ankle was palced in a cast and doctors will decide later this week if Parkinson can play Saturday.

UCLA vs. Louisville (West Regional at Pocotello, idaho) - A month ago, this very well could have been the tournament championship game matachup. But Louisville lost leading rebounder Larry Williams with a broken foot and has stumbled ever since, finally falling in the semifinal round of the Metro Seven Tournament.

Williams probably will play in this game but his effectiveness is a big question. And Louisville doesn't possess the discipline to keep up with UCLA in a run-and-shoot contest, which this game surely will become. The Bruins might be the country's best squad as long as no one succeeds in slowing down against them.

The highlight of this televised game should be the duel between UCLA's Marques Johnson and Louisville's Wesley Cox, both superb forwards. Unfortunately for Cox, he doesn't get as much rebounding help as is given Johnson - and rebounding should decide this one.

San Francisco vs. Nevada-Las Vega (West Regional at Tucson, Ariz. - They may have to utilize shifts of referees, just so the officials can keep up with the pace. The matchup is one of the most entertaining of the season, considering the talent and lack of defense on both sides.

San Francisco, which lost to Notre Dame's persistent defense last week, will find Las Vegas' more casual approach refreshing. The Dons have better size and rebounders than the Rebels, who prefer to sat outside and pop up 30-foot bombs. The key most likely will be whether San Francisco's James (Trouble) Hardy, its mooddy giant, decides to hustle. If he does, Vegas will have trouble.

Both clubs have plenty of motivation. San Francisco wants to atone for its showing against Notre Dame and Las Vegas wants to prove it can win away from home. Both clubs would like a shot at UCLA, which has consistently haunted both clubs over the last decade.

Michigan vs. Holy Cross (Mideast Regional at Bloomington, Ind.) - The Wolverines are expecting a romp in this one, and they might be right. But Holy Cross is smart enough to give Michigan trouble, at least for a while, although the Crusaders would fare much better if freshman guard Ron Perry was not ailing with a bad ankle.

Holy Cross' patience allowed it to beat Providence twice this season - and Providence defeated Michigan. Comparative scores are always risky at best, but as long as Rickey Green is not 100 per cent - he has a bad thigh bruise - Michigan is vilnerable to a patient opponent.

Tennessee vs. Syracuse (Mideast Regional at Baton Rouge, La.) - With freshman center Roosevelt Bouie getting better every game, Syracuse has emerged as the East's most consistent team. The Orangemen shoot well, run smoothly and have decent depth. But they probably don't have anyone who can cope with Tennessee's Ernie Grunfeld and Bernie King Show.

This is coach Ray Mears' dream Tennessee team, and one he feels is good enough to win the national title. It doesn't play much defense but can match baskets with anyone in the country. Syracuse will have a chance if it slows down Tennessee's fast break and makes the Vols earn their points.

Cincinnati vs. Marquette (Midwest Regional at Omaha, Neb.) - The NCAA could not have matched two teams with more contrasting styles. Marquette hates to run, Cincinnati hates to to toss more than one pass during each offensive foray.

Al McGuire has corrected Marquette's early season problems and the Warriors now are playing much more consistently. They still depend too heavily on Bo Ellis and Butch Lee for scoring, but those two may be enough to overcome Cincinnati, which loses its poise when its fast break is malfunctioning.

Kansas State vs. Providence (Midwest Regional at Norman, Okla.) - Kansas State has received little national publicity but the Wildcats finished strongly after Missouri, the Big Eight's best team, was hobbled by injury problems.

State has plenty of raw talent, led by freshman Curtis Redding, but Providence is more experienced and deeper. The Friars, despite their losses to Holy Cross, have the proper combination of ability and coaching to win the regional championship. Guard Joe Hassett is the type of streak shooter who can carry a club through a short series of games.

Arkansas vs. Wake Forest (Midwest Regional at Norman, Okla.) - This game will help to give the nation a good idea of how good Arkansas really is. The Razorbacks have a glossy record (26-1), but play in an extremely weak league and have not been tested sufficiently so far.

Despite Wake's late-season problems, the ACC fashioned a nice out-of-league record again this year and the Deacons are capable of playing excellent basketball. Some of their December magic wore off after they stopped getting the ball inside as efficiently, but if their perimeter shooting is effective, Arkansas could have problems.