LUANDA, ANGOLA, JUNE 29 -- Despite a flurry of diplomatic contacts with the United States, some formidable obstacles, including next year's U.S. presidential election, stand in the way of establishing formal ties with Washington, senior Angolan officials say they have reluctantly concluded.

But the officials, including President Jose Eduardo dos Santos, said they would press for talks in the hope of breaking a stalemate over the presence of about 37,000 Cuban troops and advisers in Angola.

Dos Santos, meeting with foreign journalists here, said today he was ready to establish diplomatic relations immediately, without any preconditions that the United States press South Africa to cease its incursions into Angola and to resolve the question of independence for neighboring Namibia.

But the president also said that Cuban forces would remain in Angola as long as apartheid exists in South Africa and Namibia remains under Pretoria's control.

Both conditions are thought likely to persist. President Reagan and South Africa have steadfastly linked a resolution of the Namibian question, by U.N.-supervised elections, to the withdrawal of the Cuban troops.

The Angolan leader presented his views shortly before four U.S. congressmen left for Washington with an American civilian pilot, who was released from jail by Angola yesterday in what dos Santos described as a "gesture of good will."

The head of the congressional team, Rep. Howard E. Wolpe (D-Mich.), who has pushed for formal U.S. recognition of the nominally Marxist Angolan government, expressed optimism after meeting with dos Santos that diplomatic relations could be negotiated.

Wolpe, noting that Assistant Secretary of State Chester A. Crocker plans to hold talks here next month with the Angolans, said, "I believe it is possible to see real progress in those discussions."

However, the Angolan who deals most directly with Crocker, Vice Minister for Foreign Affairs Vanencio de Moura, said in an interview that major obstacles stand in the way of a breakthrough, including what he termed the Reagan administration's intransigence on the Cuban issue, the influence of Cuban exiles in the United States on the presidential election and U.S. military support of anticommunist guerrillas in the south of Angola.

De Moura, who recently returned from Washington, said he favored resuming talks in Luanda with Crocker "despite the fact that they appear to have nothing new to offer." But he emphasized that the Cubans could not be withdrawn until Angola's security is guaranteed by a cutoff of U.S. aid to Jonas Savimbi's National Union for the Total Independence of Angola (UNITA) and by withdrawal of the South African forces that operate inside Angola from Namibia.

De Moura said Angola stands behind an offer it made in 1984 to implement a three-year Cuban troop withdrawal if Washington agreed to stop supporting UNITA and to press South Africa to withdraw its troops from the border region.

While U.S. officials expressed interest in the offer at the time, de Moura said, the administration has now become "part and parcel" of the conflict by providing UNITA with $15 million in covert military aid.

"We accepted that the Cubans would be withdrawn from southern Angola to the north, which is withdrawing them, in effect, from southern Africa into central Africa," said de Moura.

Noting that the Cubans would be pulled back north of the Benguela Railway, 375 miles north of the Namibian border, de Moura asked, "What more do they want to start with?"

When asked why he was convinced of the Reagan administration's capacity for exerting effective influence on an already angered government in Pretoria, the vice minister replied, "Friends can convince friends. If Mr. Reagan wants to resolve the conflict, he can talk to South Africa."

A senior western diplomat with years of experience here said he was convinced that if Washington could get a quick timetable for the withdrawal of Cubans from the southern provinces, recognition of Angola could be made acceptable to an American public largely sympathetic to Savimbi, and that real progress in negotiations could be made.

But, he cautioned, Angola then probably would seek guarantees that neighboring Zaire would no longer be used as a transport route for military shipments to UNITA, in addition to an insistence that U.S. aid to the rebels be cut off.

The diplomat also suggested that the Angolans would continue to insist on a Cuban presence in northern Angola to protect not only U.S. oil installations in Cabinda, which were attacked by South Africa's forces in May 1985, but to protect Luanda as well.

De Moura said he failed to understand the Reagan administration's "obsession" with the Cubans here, who, he said, had not been used in combat units for several years. The vice minister said, and western diplomats confirmed, that most of the Cubans are used in air and ground defense and as technical advisers.

"If you ask if the Cubans are our friends, I will tell you they are our friends," de Moura said. "They are helping us solve many problems."

But de Moura insisted that just because Angola has been reluctantly thrust into the middle of the East-West conflict does not mean that it is a vassal of either the Soviet Union or Cuba.

"We are a nonaligned country. We did not fight the Portuguese colonialists to fall into other colonialisms. Therefore we don't want to be part of this so-called East-West question," de Moura said.

Western diplomats said Angola -- like Mozambique -- continues to move steadily toward a more mixed economy, with emphasis being shifted not only toward more private-sector involvement but also away from central planning to more flexible regional planning, and with trade geared toward market-oriented countries.