October 6, 1983

Saudi Arabia is ''seriously studying'' the purchase of a marketing network abroad to sell oil products from its new refineries, the oil minister, Sheik Ahmed Zaki Yamani, said in an interview. The plan was confirmed by the industry minister, Ghazi al-Gosaibi, in a separate interview. Neither official would be more specific, but both expressed considerable enthusiasm for idea. During an interview Tuesday at his office here, Sheik Yamani also said that oil prices, depressed by the current worldwide oversupply, would begin increasing gradually.

Beset by slumping sales, money-losing small cars and intense competition from Japanese imports, Chevrolet has been the most troubled of General Motors' five automobile divisions. Within a year, though, the division plans to strike back in the small-car market with what it describes as competitively priced, profitable, high-quality products. But, in a break with the past, the new cars will come from Japan or be made in this country under Japanese supervision. In preparation for the new cars, the division dropped the ''USA-1'' slogan from its ad campaign of the last few years.

The Fortune Systems Corporation, the increasingly troubled Silicon Valley manufacturer of office computer systems, said yesterday that its board had forced Gary B. Friedman, its founder and chairman, to resign. For Fortune, the management change followed six months of mounting customer complaints about technical problems with its computers. It also comes in the midst of a shakeout in the crowded and intensely competitive personal computer sector. Fortune, based in Belmont, Calif., had been profitable in late 1982 and during the first quarter of this year. And its initial stock offering in March raised $112 million. But Fortune began losing money in the second quarter as customers became more and more dissatisfied.

The stock market recorded a strong gain in heavy trading yesterday as investors reacted to an array of positive factors. A late surge of buying propelled the Dow Jones industrial average, which was ahead only fractionally throughout most of the morning, 13.51 points, to 1,250.20. The index had recorded five consecutive losses before Tuesday's 5.39 advance. Volume on the Big Board climbed to 101.7 million shares from 90.3 million on Tuesday.

Supporters of a comprehensive immigration bill have boasted that they were taking a bipartisan or nonpartisan approach. But Tuesday's indefinite postponement of Congressional action on the bill illustrates the perils of underestimating the political importance of a powerful lobby. The Speaker of the House, Thomas P. O'Neill Jr., announced that the bill would not go to the floor for a vote this year because of strong opposition from Hispanic Americans. Members of the Congressional Hispanic Caucus today took credit for killing the bill, which they fear would increase job discrimination against members of ethnic and racial minority groups. Under the bill, employers who knowingly hired illegal aliens would be subject to civil and criminal penalties.