The South Coast Air Quality Management District, after more than 25 months of proceedings, granted today the last major regulatory permit needed by Standard Oil Co. of Ohio to build its $1 billion terminal and pipeline to send Alaskan oil east.

Although the permit still must go to the state Air Resources Board and the federal Environmental Protection Agency for concurrence, officials said the project was virtually certain to win approval at the state and federal levels.

But whether the project actually will be built remains unresolved.

Possible lawsuits by groups opposed to the project could delay or halt it. A bill to limit such delays is moving through the state legislature. Sohio, however, has expressed doubts that the bill goes far enough and has not been willing to say under what circumstances it would go forward with the project.

Today's unanimous vote was interpreted as "some progress" by Sohio vice president Richard Donaldson, but he refused to make a clear-cut statement about the company's plans. "We have had no time to assess the matter further," he said.

Sohio had flashed off and on about its intentions since March 13, when its board chairman. Alton Whitehouse, announced that it was abandoning the Long Beach terminal because regulatory delays had made the facility no longer economically attractive to the company.

Since then, after receiving promises of state and federal aid to move the project forward, the company has softened its position to say there is a glimmer of hope that it would go ahead with construction of the west-east crude oil pipeline.

In order to win permission to build the terminal and pipeline, the company had to agree to compensate for its air emissions by installing abatement device at other firms. This tradeoff was the first such compromise in the country for a project of such magnitude.

The AQMD board today gave Sohio two choices:

it could instal an $80 million scrubber on a Southern California Edison plant near the port terminal (a scrubber is a complex piece of equipment intended to clean sulfur oxides, nitrogen oxides and particulates from flue gases as they leave the large stacks at a plant).

Or it could guarantee the electric plant a 20-year supply of low-sulfur fuel, which would have the same abatement effects.

The AQMD left the choicce up to Sohio and the Air Resources Board. Both have indicated a decided preference for the srubber. The fuel would cost three times as much, according to ARB Chairman Tom Quinn.

The final agreement put altogether by the nine-member board amounted to "a shopping list" of air pollution abatement choices for Sohio and the ARB, according to A.A. McCandless, district chairman.

In fact, the agreement was reached verbally, with the actual language of the permit being left to staff members, but the board made it clear that it was not going to take the responsibility for forcing Sohio to call it quits.

Quinn said in an interview that his board would almost certainly concur with the regional district's permit language.

The key question is what protection Sohio would require to shield it from time-consuming suits by various parties who might oppose issuance of the permit or question the validity of the project's environmental impact report.