Chrysler Corp.'s board of directors yesterday approved a comprehensive plan to reorganize the company into four operating units.

Chrysler insiders said that the reorganization, effective immediately, means that the company is moving to resume its role as a multinational corporation with interests in automotive and nonautomotive businesses.

The plan also means that Chrysler Chairman Lee A. Iacocca, now 61, probably will remain with the company for at least four more years, according to company sources.

There have been widespread rumors that Iacocca would leave Chrysler by 1987 to run for the U.S. presidency in 1988. Iacocca repeatedly has denied those rumors, and one company source said that the chairman "is becoming more irritated" with suggestions that he has national political ambitions.

Still, some auto industry analysts speculated yesterday that reorganization is a part of Iacocca's strategy to bail out gracefully and run for office. But a close Iacocca associate, who requested anonymity, called that speculation "wrong, wrong, wrong."

Iacocca has a contract to stay on as chairman through 1986, the associate said. The contract also gives Iacocca the option to keep his present job past his 65th birthday, the associate said.

"He does not have any intention of jumping out" of Chrysler, the associate said emphatically. "He's so strong, he can stay on as long as he wants to. He's planning to do more to expand Chrysler beyond its present businesses," the associate said.

The reorganization frees Iacocca "from spending time popping into 10-day-sales report meetings," the associate said.

Under the terms of the plan approved yesterday, Chrysler will have an automotive group, Chrysler Motors; a financial operation, Chrysler Financial Corp.; an aerospace-defense group, Gulfstream Aerospace Corp., and a high-technology research-and-development group, Chrysler Technologies.

Each of the groups will be an autonomous operation, with its own management. Chrysler officials said yesterday that the company also is examining the possibility of legally transforming Chrysler Corp. into a holding company, with the groups existing as subsidiary companies.

"We are modernizing the company's structure to enable us to manage our business better," Iacocca said yesterday in Detroit. "Chrysler is a growing company, expanding its operations and becoming more international and complex. We can no longer continue to run it like a North American car and truck company," he said.

Chrysler, a 60-year-old corporation, now ranks as the nation's third-largest car producer. Prior to 1979, when Chrysler moved perilously close to bankruptcy, the company was a major defense contractor, and it had extensive overseas operations.

Iacocca sold the defense business and eliminated most of the company's overseas enterprises in his successful effort to move Chrysler back to profitability. The company reported record third-quarter, before-tax earnings of $451.8 million, and third quarter net earnings of $316.2 million, or $2.75 a share.

The newly solvent Chrysler has been on an acquisition binge in the past year, buying finance companies, such as FinanceAmerica and E. F. Hutton Credit Corp. Chrysler also entered joint ventures with Japan's Mitsubishi Motors Corp., in which it has a 24 percent interest, and with Korean auto maker Samsung.

Chrysler also owns 12 percent of Peugeot, a French auto maker.

Auto manufacturing will remain Chrysler's "core business," Iacocca said. The reorganization and diversification efforts are designed "to help the company grow and to strengthen the car and truck business," he said.