San Diego and Atlanta are cofavorites at 3 to 1 in the Super Bowl line posted this week in Las Vegas. Philadelphia is the solid third choice at 7 to 2, followed by Cleveland, 5 to 1; Buffalo, 6 to 1; Dallas, 8 to 1; Los Angeles, 10 to 1; Houston, 12 to 1, and Minnesota and Oakland, both 15 to 1.

Home-field advantage, more than any other factor, dictates the prices. The Chargers and the Falcons will be the host teams as long as they survive. Should either falter, the Browns and Eagles would enjoy the home advantage for the conference championship games. The Bills and Vikings will play before their fans only if they and the wild-card qualifiers wind up in the title contests.

For the first time in many seasons, the National Conference is strongly represented among the 10 playoff squads. Los Angeles, Atlanta, Philadelphia and Dallas all are solid teams and Minnesota is better than most observers realize. They are as capable, collectively, as the American Conference teams.

I think the Rams are as good, at this particular time, as any entrant in the round of 10. Had they won the NFC's West Division, instead of finishing one game behind Atlanta, they would have been the cofavorite with San Diego in the Super Bowl futures.

Now, in order to gain the national championship, L.A. will have to defeat the Cowboys in Dallas, the Eagles in Philadelphia, the Falcons in Atlanta (probably) and the AFC representative in New Orleans. That's a tough road to travel, thus the 10-to-1 price. Even so, I give them a real chance, while San Diego has only to duplicate its Monday night performance against Pittsburgh in order to succeed the Steelers as AFC, if not world, champs.

The action begins Sunday with Dallas favored by 3 over Los Angeles in Texas Stadium and Oakland a 1-point favorite at home against Houston. I'll go with the Rams and Raiders for $1,000 each. Two weeks ago, believing Vince Ferragamo to be injured and Pat Hayden the likely quarterback for the Rams, I picked Dallas at Los Angeles. Ferragamo recovered quickly from the sore ribs he suffered in Buffalo and made that pick look foolish, 38-14.

The Cowboy cornerbacks were horrible that Monday night, and they appeared to be just as inept Sunday in the second half against Philadelphia. I had thought Dallas' young secondary was improving steadily this season. Recent evidence suggests otherwise. What's important here is that Los Angeles' superb offensive line will neutralize Dallas' strong pass rush, giving Ferragamo time to exploit the Cowboy weakness. The Rams should be able to run on Dallas, particularly in Harvey Martin's direction.

The Dallas offense will fare better than it did in Los Angeles, however, unless Danny White has one of his dismal days. White can also be quite effective. He is the key to the Cowboy's chances. Ferragamo is more reliable, a sharper passer, and faces a much weaker pass defense than White. On balance, the Rams should be favored. Take the points.

Oakland enjoys less of an edge in the matchups but has the advantage of playing at home. I have been waiting for 16 weeks for the Houston offense to bust loose. Apparently, it's not going to happen, not with the Oilers playing so conservatively in the first half. Kenny Stabler has been less than scintillating most of the season, letting Earl campbell and Dave Casper do the bulk of the work.

The Raider defense probably is the most underrated unit in the NFL. It will have to be at its best to check Campbell, and Jim Plunkett must stay away from the turnover. But Oakland's offensive line should have a good day. aI give the Raiders a slight edge, both ways, on the line of scrimage, and that's where the outcome will be determined, narrowly.