January 12, 1981

The Oakland Raiders, a team that was considered by some the weakest in its division even before the starting quarterback broke a leg, won the American Conference championship game today, defeating the San Diego Chargers, 34-27. They shocked the Chargers by building a three-touchdown lead in the first half, and refused to allow the Chargers a chance to come back by holding the ball for the last 6 minutes 43 seconds. The Raiders were led by Jim Plunkett, the quarterback who was out of work before he joined the team as a free agent in 1978, and who asked to be traded earlier this year when he expected to have virtually no playing time for the third straight season. He completed 14 of 18 passes for 261 yards and two touchdowns, and ran for a score. Just as significantly, he was not intercepted.

It is third period in Mr. Chase's classroom, and Rocky has just inhaled the Blob. The students are having a good time in the film-animation class at Columbia High School here. One is working the motion-picture camera while his co-producer engineers supervise the inhalation of one clay figure by another between bright lights and a painted backdrop. Others interrupt their own projects to voice approval and offer suggestions. Some parents' and taxpayers' groups suggest that in the face of rising inflation and decreasing enrollments - and at a time when many students have difficulty even learning to read - courses in film making should be the first of many ''nonessentials'' to be cut from the curriculum. Across the country, school boards have eliminated courses that taxpayers have deemed frills. A spokesman for the United States Office of Education said it was generally a difficult time for arts education throughout the country. In New York City's public schools, for example, a school board spokesman said that two-thirds of the high school art and music teaching positions had been eliminated since 1975.

Saudi Arabia, which had been supplying at least 12 countries with extra crude oil to offset shortages caused by the Iraq-Iran conflict, has not yet renewed its ''war relief'' contracts for 1981, Petroleum Intelligence Weekly reports in today's edition. Nervous consuming nations are trying to convert the temporary arrangements into more secure long-term contracts with the Saudi Government, the weekly newsletter said. ''It is uncertain whether any realignment of volumes or clients is planned among the 12 to 15 countries receiving 500,000 to 600,000 barrels daily of make-up oil, or whether the lag is due to normal administrative delay,'' P.I.W. said.

TWO hungry young animals with Phi Beta Kappa feet rushed into this town's growing company of demigods, adding another chapter to the Philadelphia Story in the game for the championsip of the National Conference of the National Football League. Wilbert Montgomery, a greyhound with muscles, and Leroy Harris, who runs like an infuriated beer truck, ripped through and around the Dallas defenses for the points that qualified the Eagles for Super Bowl XV two weeks hence. On the first time Philadelphia had the ball, Montgomery caught the Cowboys by surprise and raced 42 yards all by himself for a touchdown. Late in the third quarter, Harris cut back through the middle and went 9 yards to the end zone, and barefooted Tony Franklin added the other points in a 20-7 victory.

Ronald Reagan's economic advisers say they are timing their preparation of his economic package to set the stage for a dramatic 100 days of Congressional action on the Federal budget, aimed at avoiding a legislative stalemate. To heighten the drama further, the Reagan advisers said in interviews, they are considering new ways of applying pressure, principally the idea of threatening to veto further increases in the limit on the Federal debt, if the package is not approved. Such vetoes would severely hamper -even halt - the Federal Government. Affected would be such popular activities as the payment of Social Security benefits. May 15 Deadline Seen as Key Recognizing that the budget cuts they will eventually recommend are likely to be highly controversial, the advisers say they want to improve their chances in Congress by having them voted on as a package by the May 15 deadline for initial action on the budget for fiscal 1982.