Senate Majority Leader Robert C. Byrd (D-W.VA.) appeared on the brink of formally endorsing the strategic arms limitation treaty yesterday as the Senate Foreign Relations Committee prepared to begin voting on it Monday.

Although Byrd insisted at a press conference that he hasn't quite made up his mind whether to endorse the arms treaty with the Soviet Union, which is President Carter's single most important request to Congress this year, Byrd revealed that he had met with "eight to 10 senators" privately Friday to seek some idea of how much defense spending must be beefed up to quell fears of national-security dangers.

Byrd said that if "the McGoverns and the Nunns, the Stennises and the Moynihans" could get together and draw some compromise "fine line" on what to spend and on certain other national security concepts, "then we could put together a two-thirds majority on the SALT treaty."

He said he had asked Majority Whip Alan Cranston (D-Calif.) and Sen. Daniel P. Moynihan (D-N.Y.), who has been sharply critical of the Soviets, to head special units to study both arms reduction and needed increases in defense spending. The Friday meeting, he said, included several Republicans but he declined to name anyone present.

Byrd said he has told the White House flatly that the treaty won't come to the Senate floor for a final vote until and unless it hands over five-year military spending projections, with some details, which he said in many cases firms lobbying for defense contracts already know. He said the president had agreed to supply the projections.

As Byrd appeared to be nearing open endorsement of the treaty, Sen. Charles H. Percy (R-Ill.) announced in Chicago that he will vote for the treaty provided the Senate adopts two "understandings," which he expects. One makes clear the United States can continue transferring defense technology to its allies; the other requires Senate approval before a three-year "protocol," limiting some missile ranges, can be extended further.

The Foreign Relations Committee on Friday killed by a 10 to 5 vote a proposal by Sen. John Glenn (D-Ohio) to delay any consideration of the treaty until it can study the implications of the five-year projections, once they are received from Defense Secretary Harold Brown. Instead, it agreed to start voting Monday. Glenn was joined by Republicans Howard H. Baker (Tenn.), Richard Lugar (Ind.), S.I. Hayakawa (Calif.) and Jesse Helms (N.C.).

Byrd, who said he favors televising the Senate SALT debate provided a time limit can be agreed on, said his own reading of "backup materials" has convinced him that "funding more money" to beef up U.S. arms is a must with or without the treaty in view of Soviet strides. He said that on verification of the SALT agreements, the "bottom line" of the Senate Intelligence Committee's assessment is "that without SALT II our ability to monitor [Soviet arms] is going to be less than that with SALT II -- the committee seemed to be pretty much unified on that point."

Byrd also told reporters:

He doesn't particularly like GOP presidential candidate John Connally's concept of using U.S. forces to keep peace in the Mideast and he thinks Carter's Camp David approach is better.

Gasoline lines "will be back, no question they'll be back," so it's good that Congress is moving to pass major energy and synfuels legislation.

Attaching anti-abortion and other substantive legislative provisions to appropriations bills and thereby holding up the U.S. budget is becoming a "legislative abomination . . . a nightmare . . . legislative blackmail" and he hopes to get together with House leaders on some way to control it.

With luck, Congress might be able to complete energy, synfuels, appropriations and windfall-profits legislation, and then complete SALT, by Thanksgiving, but "we may be in till Christmas" though he doesn't really believe it will be that long.