Judging by the point spreads on the NFL's conference championship games, there is little suspense as to who will play in Superbowl XIX.

Sunday, Miami will host Pittsburgh for the AFC title while San Francisco will entertain Chicago for the NFC championship. The number on each contest is 10, the home team favored. Had Denver and Washington not been upset Sunday, the spreads, naturally, would have been smaller.

Already a question heard frequently is: "Who will be favored, Miami or San Francisco, in the Super Bowl?" The answer is San Francisco, probably, since the game will be played in Palo Alto, on the Stanford campus, making it a "home" game for the 49ers.

"It depends a little bit on how the two favorites play this week," a Las Vegas linesmaker said yesterday. "There is no way Miami will be favored, in my opinion. But if the Dolphins win impressively over the Steelers, and the 49ers have to struggle slightly in beating Chicago, the game could open even. Otherwise, it looks like it would open with San Francisco favored by a point or two."

Fans in Chicago and Pittsburgh have every right to feel that this information is presumptuous. After all, Denver was favored by five and Washington by seven at this time last week. But few observers would argue that Miami and San Francisco deserve their strong support. ABC undoubtedly dreads the prospect of televising a Pittsburgh-Chicago matchup Jan. 20.

I can't see either of the underdogs pulling off another surprise this week. The Redskins and the Broncos were much more vulnerable, in that respect. But 10 makes covering the spread a truly sporting proposition. I will go with one favorite and one underdog for $750 each.

Miami has too much airpower for the Steelers. The strength of the Pittsburgh defense is the pass rush. It is a strength that will be negated by the superb protection the Dolphins give Dan Marino.

I concentrate on watching the line play -- as much as the network cameras provide -- and the best offensive lineman in pro ball this season might well be Dwight Stephenson, the Miami center. Take a look at his strength and quickness, at how the five-year pro from Alabama gets back in time to help block for the passer after snapping the ball. I doubt any center has ever done it better.

Marino will have time to throw, as he always does. The two speedy Marks, Duper and Clayton, will give the Steelers' secondary more than it can handle. The Steelers probably will shut down what little running game Miami has, but it won't matter. The Dolphins live or die with Marino's arm. He should enjoy another excellent day. Miami's point total will be in the mid-30s or higher.

That does not guarantee that the Dolphins will cover. Stories out of Miami now would have us beleve that Don Shula's club has regained its confidence defensively. I'm not convinced. Good efforts against Dallas and Seattle can be misleading, inasmuch as these teams are weak offensively. Neither has a running attack.

Pittsburgh can run. What with the strength of Frank Pollard and the swiftness of Walter Abercrombie operating behind a good young line headed up by veteran center Mike Webster. My fear is that the Steelers will be able to run enough to make Mark Malone's passing to John Stallworth and rookie Louis Lipps effective. That would establish ball control, keep Marino on the bench longer than I'd like, and put covering 10 points in jeopardy.

That is the key. Will the Steelers be able to run? If they can't, the Dolphins romp. I will give the 10, happy in the thought that tackle Mike Charles has recovered from his injury in time to help the Miami defense in the playoffs.

San Francisco has too many offensive tools and too much balance, as a squad, to lose to Chicago. At least, that's how it looks on paper.

The Bears don't worry about such appearances. They simply come to maul the opposition's offense. To them, Joe Montana is just another pretty face.

Dave Hampton is in the Randy White class as a defensive tackle while Richard Dent made remarkable progress in his second season at defensive end. Throw in the savage linebacking of Mike Singletary and you know why Chicago can never be dismissed lightly.

I had planned, early in the year, to pick the Bears throughout the NFC playoffs. Then, Jim McMahon was injured and their quarterback situation became ludicrous.

Steve Fuller lacks the necessary skills for the most demanding position in football. He is smart enough, however, not to make costly mistakes on most occasions. If he avoids the big turnovers, Chicago's defense can keep its offense in the game.

The 49ers' short passing game -- Joe Montana to Dwight Clark is a great way to counter any all-out blitz -- will move the ball, helped by Montana's scrambling ability. But Wendell Tyler is one of the most dangerous (to his team) fumblers in the league, while Walter Payton seems to enjoy the pressure situations. I have a hunch Payton will find a way to help put more points on the board than most people anticipate. It's chancy, but I'll predict San Francisco to win and Chicago to cover. THE RECORD

Last week's results: Miami, giving 6, defeated Seattle, 31-10, plus $750; San Francisco, giving 10 1/2, defeated the New York Giants 21-10, plus $250; Washington, giving 7, lost to Chicago 23-19, minus $550; Pittsburgh, getting 5, defeated Denver 24-17, plus $250.