Secretary of State Cyrus R. Vance and Soviet Foreign Minister Andrei A. Gromyko held a lengthy final meeting today on the disputed Soviet combat brigade in Cuba and declined to say later if any progress had been made.

Vance immediately flew to Washington ot brief President Carter and the National Security Council. Gromyko said he will fly back ot Moscow Friday.

The fact that no more U.S.-Soviet meetings were announced and that Gromyko is returning to Moscow tihout seeing President Carter was interpreted as a sign that the impasses between the two nations has not been broken.

Because of the sensitivity of the subject, part of the nearly 3 1/2-hour session at Vance's hotel was a private conference between the two men, with only interpreters present. Another indication of the sensitive nature of the subject was that Gromyko declined to conede publicly that U.S. charges of a Soviet combat brigade were even discussed.

Emerging from the lengthy conference into a crush of reporters and photographers, Vance and Gromoyko appeared solemn and ill at ease. They agreed the talks were "serious" and announced in advance they would not discuss their substance.

No additional meetings with the Soviets on the subject were announced, and U.S. officials in the Vance party would give no indication whether three weeks of talks left any hope for a negotiated solution through continued diplomatic dialogue.

State Department spokesman Hodding Carter cautioned reporters against any speculation.

Carter did not foreclose the possibility that Vance may change his schedule, which is to take him to New Haven for a speech at Yate Saturday and to Panama for a ceremony about the canal late Sunday.

Vance is to meet Friday morning at the White House with President Carter, Secretary of Defense Harold Brown and national security affairs adviser Zbigniew Brzezinski in a regular weekly breakfast on foreign policy matters.

Failure to resolve the dispute over the brigade through diplomatic means could trigger unspecified U.S. counteractions promised by President Carter.

Meanwhile, White House press secretary Jody Powerll today identified seven members of the panel of former government officials named to advise the president on the troops issue.

The seven: Clark Clifford, a Washington attorney who has been an adviser to several presidents; McGeorge Bundy, national security affairs adviser too President John F. Kennedy; Brent Scowcraft, national security affairs adviser to Presidents Richard M. Nixon and Gerald R. Fords; John McCloy, a Wall Street lawyer and former holder of numerous diplomatic posts; John McCone, former director of the Central Intelligence Agency; David Packard, former electronics executive and former deputy secretary of defense; and Sol Linowitz, on of the negotiators of the Panama Canal treaties.

Powell said five other citizens from outside the administration were being consulted, but he refused to identify them or their duties. Administration sources, however, said two are former secretaries of state Henry Kissinger and Dean Rusk.

For his part, Vance continued to maintain a low-key public posture. In an address here today to the Foreign Policy Association, Vance said that, while the United States is concerened about the Soviet brigade, it wishes to keeep each part of its relationship with the Soviet Union "in proper perspective."

This appeared to be a bid to discourage an across-the-board confrontation with the Soviets that would destroy the results of seven years of negotiations on SALT II and raise tensions in many parts of the world.

Several Western European foreign ministers and other allied diplomats who were briefed on the brigade dispute by Vance here this week reportedly expressed their concern about the effect of a major U.S.-Soviet dispute.

Some of these countries see stable U.S.-Soviet relations as fundamental to their own national policies of detente with the communist world. The demise of SALT II and the beginning of a new U.S.-Soviet confrontation would likely set off intense tremors in these allied countries.

Despite Vance's explanations, the Soviet's as well as many Uropeans appear to be puzzled about the brigade issue. In the briefings for alies, Vance described how the issue arose and how it is viewed withih high circles of the U.S. government.

Today's meeting was the seventh in a series of U.S.-Soviet negotiating sessions on the issue since Sen. Frank Church (D-Idaho) made public Aug. 30 the official U.S. conclusion that a Soviet combat brigade is stationed in Cuba.

The first meetings, between Vance and Soviet Ambassador Anatoliy F. Dobrynin, centered on expressions of U.S. concern and a question-and-answer dialogue in which Washington sought information from the Soviets about the operations and purpose of the brigade. On the day of the first Vance-Dobrynin meeting, Sept. 10, the Soviets made public a front-page Pravda editorial, which remains their most detailed public comment, rejecting the U.S. charges and maintaining that neither the numbers nor the function of Soviet military personnel in Cuba has changed since 1962.

From the outset, the United States announced that the "status quo" is unacceptable. But only a week ago, on Sept. 20, did Washington put forward through Dobrynin specific suggestions for a diplomatic settlement. These ranged from withdrawal of the combat force, which already had been rejected informally by the Soviets, to measures for removing "the combat capability" of the force by reassignment of its officers and transfer of its major equipment to the Cubans.

At the first Vance-Gromyko meeting last Monday, Gromyko reportedly persisted in the position that the Soviet force is not a combat unit, is nothing new and does not violate any U.S.-Soviet understandings regarding Cuba or threaten the security of the United States.

President Carter and Brzezinski have made it increasingly clear that the United States will order a series of compensatory actions to "change the status quo" if the matter cannot be resolved diplomatically. The nature of these actions has not been announced.