It may be 40 years before historians and journalists can get at the tape recordings that Lyndon Johnson made during his White House years, but based on records kept during his presidency and transcripts of several of his earlier taped conversations, there is a treasure of Johnson lore to be heard and read.

It has been known for some years that Johnson had many of his Oval Office phone conversations recorded and that he taped some meetings in the Cabinet Room during his presidency.

But Johnson's habit of recording conversations, like that of other presidents, may be more extensive than is generally believed. Public records at the president's library suggest that at certain stages of his presidency nearly every telephone call in and out of the Oval Office was recorded, unless it was on one of Johnson's many private lines. How many of those recordings still exist is not known.

An examination of certain presidential logs kept in June and July, 1964, shows that Johnson recorded conversations with FBI Director J. Edgar Hoover, Sen. Edward M. Kennedy, Secretary of State Dean Rusk, House Speaker John McCormack (D-Mass.), Rep. Carl Albert (D-Okla.), Clare Booth Luce, civil rights leaders Roy Wilkins and Whitney Young, Averell Harriman, Sens. Mike Mansfield (D-Mont.), James O. Eastland (D-Miss.), George Smathers (D-Fla.) and Clinton P. Anderson (D-N.M.), Secretary of Labor Luther Hodges, budget director Kermit Gordon and various White House aides.

The library's public files already contain transcripts of telephone conversations Johnson had with other political figures during the pre-presidential years. Some of these are based on shorthand notes taken by a secretary listening to the conversation.

These pre-presidential transcripts, however, are not organized into one file, so no one knows just how many there are.

At least three are known. One is between Vice President Johnson and Theodore Sorensen, an aide to President Kennedy, on June 3, 1963. If it is indicative of other tapes, the Lyndon Johnson described by aides for so many years will someday be available to the general public.

"So much of the essence of the man came across in personal conversations and was not committed to paper that historians will find any transcript of some interest," said Harry Middleton, director of the LBJ library.

In the June, 1963, conversation with Sorensen, the contents of which have been previously disclosed, Johnson, Kennedy's vice president who was former Senate majority leader, poured out his frustrations over the way the White House was handling Kennedy's civil rights program.

". . . you haven't done your homework on public sentiment, on legislative leaders, on the opposition party or on the legislation itself," Johnson tells Sorensen.

He urges the White House not to send Congress the civil rights bill until other parts of Kennedy's legislative program have been acted upon. "I'd move my children on through the line and get them down in the storm cellar and get it locked . . . and then I'd make my attack," Johnson says.

"If I were Kennedy I wouldn't let them Republicans call my signals," Johnson says at another point. "I'd pass my program, make them stand up and vote for it. While I was doing that I'd go into the South a time or two myself . . . . I think I know one thing, that the Negroes are tired of this patient stuff and tired of this piecemeal stuff and what they want more than anything else is not an executive order or legislation, they want a moral commitment that he's behind them."

Later, Johnson tells Sorensen: "I want to pull out the cannon. The president is the cannon. You let him be on all the TV networks just speaking from his conscience, not at a rally in Harlem, but at a place in Mississippi or Texas or Louisiana and just have the honor guard there with a few Negroes in it. Then let him reach over and point and say, 'I have to order these boys into battle . . . . I don't ask them what their name is, whether it's Gomez or Smith or what color they got, what religion. If I can order them into battle I've got to make it possible for them to eat and sleep in this country.' Then . . . everybody . . . goes home and asks his wife, 'What's wrong with this?' and they start searching their conscience. Every preacher starts preaching about it. We ought to recognize that and put them busy."

Another transcript reveals a Jan. 11, 1955, phone call between Johnson, then Senate majority leader, and Sen. Estes Kefauver (D-Tenn.), who wanted an assignment to the Democratic Policy Committee in the Senate. Johnson tells him the job is going to someone else.

"I have never had the particular feeling that when I called up my first team and the chips were down that Kefauver felt he ought to be identified and ought to be on that team," Johnson tells Kefauver.

"I will let my hair down on this point, Lyndon," Kefauver replies. "Honestly, you never have given me a break since you have been the leader."

Transcripts from these early days may not be completely accurate. A note attached to a transcript of a Feb. 12, 1958, conversation with Kefauver indicates that Johnson had an eye on how historians would treat him.

"George," the note says, apparently referring to Johnson aide George Reedy. "Edit this, cut out all the uh's and stuff. LBJ."

It is not clear when Johnson's White House taping system was established, or just how it worked. Officials at the LBJ Library believe that secretaries activated the recorders on orders from the president.

When Johnson left the White House in 1969, he entrusted the tapes from his presidential days with one of his closest aides, Mildred Stegall. Stegall brought the tapes to the LBJ Library shortly after Johnson died on Jan. 22, 1973, and said the former president wanted the contents sealed for 50 years.

They are contained in eight cardboard boxes, each holding about one cubic foot of material. Library officials put them in the security vault and to date there has been no effort even to begin to catalog the contents.