Soon after the FBI started its formal campaign of disruption and dirty tricks known as Cointelpro, Director J. Edgar Hoover seized on the notion that America's No. 1 and No. 2 Communists were living in bourgeois splendor.

FBI agents in New York were accordingly instructed to begin documenting the life-style of Communist Party national chairman William Z. Foster and general secretary Eugene Dennis in an effort to create a rift between them and the party's fast disappearing rank-and-file.

It created tensions that lasted for months - not between Communists, but between the chief of the FBI and his men in the field. The 53,000 pages of records about the bureau's controversial counterintelligence programs of harassment indicate that most harassed were occasionally the farflung agents of the FBI.

Hoover, for instance, repeatedly refused to accept the continued insistence of his New York office in 1956-57 that the top Communists in the land weren't living high on th hog.

"Foster and Dennis reside in apartments located in tenement districts considered to range from modest to poor," Hoover was told on Nov. 14, 1958. "The interiors of their apartments are not lavishly furnished. They have no servants. Mrs. Dennis does her own laundry. Mrs. Foster sends hers out . . . Their food bills are modest . . ."

What's more, the memo continued, "Foster receives a weekly salary of $70 from the Communist Party. Dennis receives a weekly salary of $67.50 . . . Neither Foster nor Dennis is known to have an extensive expense account with the Communist Party or an outside income."

That was not what J. Edgar Hoover wanted to hear.

"On an overall basis they are living musn better than the average Communist and probably beyond the means of the average Communist member," the FBI director insisted in a Nov. 23, 1956, memo to New York. He noted that both Foster and the ailing Dennis took long vacations and had cars and chauffeurs provided by the Communist Party in the United States. Calling for more information along those lines, Hoover declared:

"The bureau is still interested in publicizing the manner in which the CP membership supports Foster and Dennis as a means of causing further disruption within the ranks of the organization."

The debate lasted all winter. Hoover pointedly informed his New York agents on Jan. 22, 1957, that their memos still "fell short of the desired information" and made clear that he was tired of their "editorializing on reasons why the living habits of these two party leaders should not be publicized." He said he wanted more data, including the salary of the two chauffeurs, and concluded:

""Rank-and-file party members all over the United States have sacrificed considerably for the party and all pertinent information indicating that these party leaders are living well off party funds might be used to further discourage the rank-and-file members from continuing their party support."

New York dutifully served up a laborious accounting of the two Communists' finances, from their savings accounts to utility bills to the fact that Dennis used the subway about once a week. The report also included the party paid salaries of the two chauffeurs. Each got $50 a week, not much less than Foster, who was still getting $70, or Dennis, who was now said to be earning only $65.90.

A few days later, FBI headquarters finally gave up in a terse, grudgingly worded note that suggested it was all New York's fault. "The investigation of the New York Office failed to develop sufficient information to provide the basis for an effective article in this connection," FBI intelligence division chief Alan H. Belmont was told by one of his aides. "We propose to take no further action in this connection at this time." CAPTION: Picture 1, WILLIAM Z. FOSTER; Picture 2, EUGENE DENNIS . . . Hoover's theory couldn't be squared with their salaries of $70 and $67.50.