It was, Ambassador Ellsworth Bunker said afterward, "just like the old days" in Saigon: Gen. William C. Westmoreland fervently defending his performance as American commander in Vietnam; skeptical reporters trying to ask him tough questions; strong feelings all around. For two hours yesterday, the Vietnam war came back to the Army-Navy Club in downtown Washington.

An emotional and angry Westmoreland called a news conference to denounce a CBS television documentary, aired last Saturday night, which accused him of covering up intelligence information on North Vietnamese and Vietcong strength during 1967.

The program was "a preposterous hoax," Westmoreland said--the product of "premeditated malice" on the part of CBS correspondent Mike Wallace, who conducted a "star chamber" inquisition of him, Westmoreland asserted. The general acknowledged that he had written some of his most heated words "at 3 o'clock this morning."

Westmoreland assembled a reunion of old Vietnam hands to join in his attack on CBS. Besides Ambassador Bunker, who is still active at age 87, there was George Carver, for years the CIA's top Vietnam expert; Lt. Gen. Daniel Graham, a former intelligence officer in Saigon and later director of the Defense Intelligence Agency, and Gen. Philip Davidson, once the top Army intelligence officer in Vietnam. Barry Zorthian, the American Embassy spokesman in Saigon at the height of the war, watched from the audience.

Those who spoke agreed on one main point: there was no "conspiracy" involving Westmoreland and themselves to cover up intelligence information showing sharply larger enemy forces in Vietnam in 1967, the year before the Tet offensive.

At the beginning of the CBS documentary, Wallace said CBS believed there was "a conscious effort, indeed a conspiracy, at the highest levels of American military intelligence to suppress and alter critical intelligence on the enemy in the year leading up to the Tet offensive." A full-page CBS ad for the program that ran in The Washington Post and The New York Times was headlined "Conspiracy."

On other points there was some disagreement among the group. As so often happened in Vietnam, there were disputes over statistics. Afterwards, Carver of the CIA disassociated himself from some of the things Gen. Graham said. Old Vietnam hands had to agree with Ambassador Bunker that it looked like the old days again.

Westmoreland charged that he had been "ambushed" by CBS, because the network arranged to interview him on "the broad topic of intelligence," without hinting what it really was after. Later, CBS producer George Crile read a reporter the letter he said he sent to Westmoreland last May 15 spelling out in some detail the subjects Wallace subsequently covered in the interview.

At issue, besides CBS's conduct and the charge of a "conspiracy," is a 15-year-old intellectual battle about how many people the Vietnamese communists had on their side in South Vietnam. CBS found a group of retired military officers who served in the intelligence branch of American headquarters in Saigon during 1967 who said, on camera, that figures were fudged, information suppressed and the truth hidden about true enemy strength.

According to these officers, when American analysts produced new numbers showing enemy strength to be higher than previously realized, the numbers were either altered downward or suppressed. One senior intelligence officer whom Westmoreland himself praised, Col. Gaines Hawkins, said that when he originally told Westmoreland that the figures should be revised upward, the commander replied: "What am I going to tell the press? What am I going to tell the Congress? What am I going to tell the president?"

Westmoreland did not deny this account to CBS. At yesterday's news conference, Westmoreland hotly disputed the suggestion that he knew the enemy was stronger than he admitted in public or private communications to Washington. Westmoreland acknowledged that some of his staff produced new estimates in 1967 showing higher enemy strength, but insisted that this only involved "political cadre" or people who "were essentially noncombatants and had been there all along."

Gen. Graham, whom Westmoreland asked to give a more detailed rebuttal of the CBS documentary at yesterday's conference, made the same point. He showed a brief passage from the CBS documentary on a videotape machine in which Col. Hawkins appeared to acknowledge that the statistics in question referred only to "the political order of battle," not to armed Vietcong.

However, the clip from the documentary that Graham showed was edited to cut out Hawkins' final words, when he said that the political order of battle included "the Vietcong's political bureaucracy and the guerrilla strength." The guerrillas were armed.

Asked about this use of editing to distort Hawkins remarks, Westmoreland made no reply. Asked if he really meant to say that the only dispute involved noncombatant political cadre, Westmoreland changed his original version and said "no, no, they clearly were not" the only category under dispute.

Interviewed later by telephone, Hawkins, who now runs a retirement home in West Point, Miss., recalled that when he originally presented his revised estimates of enemy strength to the top command, Westmoreland instructed him to "take another look at these figures."

This meant reduce them, Hawkins said, so he arbitrarily reduced his estimates of Vietcong strength. Later he did this several times, and then argued for the new Military Assistance Command Vietnam figures that he didn't personally believe in inter-agency disputes with the CIA, which actually favored the higher numbers he originally came up with.

Hawkins said the CBS program was a good one. He said Westmoreland had telephoned him four times on Sunday to urge him to say his remarks were taken out of context, but Hawkins said they were not.

"The war is over now," Hawkins said. "I think it's a good time to go back and make an assessment of it."

It would take a book to explain all the details of this old intelligence dispute that can still make men's blood boil. To match the insistence of the top-level officials who spoke at yesterday's news conference, there are equally fervent assertions from more junior officers who served in Vietnam that the figures were fudged.

For example, Westmoreland and Graham insisted that intelligence on North Vietnamese infiltration into South Vietnam showed that only about 6,000 or 8,000 men were coming into the South every month during the fall of 1967.

But former Lt. B. A. Gattozzi, an intelligence officer who wrote the estimates of enemy strength inside American headquarters in Saigon, insisted in an interview yesterday that there was a spurt in infiltration that fall that was never reported to Washington. The figures produced by the analysts, he said, showed there were 25,000 to 35,000 North Vietnamese soldiers coming into the South monthly that fall.

These figures were suppressed somewhere in the upper reaches of the chain of command, Gattozzi asserted.

Westmoreland made one surprising revelation at the news conference. He said he had told President Johnson in March, 1967, that "the war could go on indefinitely" if the United States did not cut off the Ho Chi Minh Trail on which the North Vietnamese sent their reinforcements to the South, a step neither Johnson or his successor, President Nixon, would authorize. The idea that the war was unwinnable did not enter Westmoreland's public statements when he was commander.