In a major victory for President Carter, the House yesterday overwhelmingly approved a bill making possible unprecedented changes in the 100-year-old federal civil service system.

After the final 385-to-10 vote, congressional leaders predicted that the legislation would have an easy time in a House-Senate conference committee because of the bill's similarity to one passed by the Senate last month and to the original administration proposal.

Unless there are some surprises, the leaders said, a final bill should be on President Carter's desk before Congress adjourns in October.

In a telephone call between Camp David and a room in the Capitol, the president told those who had led the fight for the bill that he was delighted at the news.

Rep. Morris K. Udall (D-Ariz.), who had led the arduous fight for passage in the House, said the bill signals a "new day" for the government's 2.1 million civil servants, with greater rewards for the many good workers and a much speedier exit for those who "don't cut the mustard."

Republicans, led by Rep. Edward Derwinski (Ill.), praised the president for taking on the bureaucracy and called the bill's passage a "historical bi-partisan victory for the people."

The only major element of his plan that the president lost was his proposal to curtail sharply veterans' preference rights in federal hiring and job retention. Both the House and the Senate, under election-year pressure from organized veterans groups, stripped the proposal out of their bills by wide margins.

In a key vote yesterday, House prolabor forces and Republican right-wingers halted a fractious debate and joined hands under a "good government" banner, passing 380-to-0 a crucial compromise on federal labor-management practices. That issue, more than any other, had threatened to kill the bill.

The bill as amended killed many of the controversial concessions given to federal employes' unions by the original House version of the bill as reported out by the Post Office and Civil Service Committee.

But it gave the unions several items that they have long sought, including a somewhat broadened [WORD ILLEGIBLE] of bargaining and grievance, automatic voluntary dues withholding, and an independent labor authority patterned after the private sector system.

It also gives the force of law to rules governing federal recognition of unions so that they no longer can be revoked by presidential fiat.

Among the major elements of the bills approved by both the House and Senate are:

Creation of a Senior Executive Service (SES) in which 9,000 federal managers will be allowed to trade some of their present job security for higher pay and other rewards for superior performance, and risk firing or demotion for poor work. (No more than 10 percent of the SES could be political appointees, as opposed to career civil servants.)

The House version, under an amendment sponsored by Rep. Gladys Noon Spellman (D-Md.), would limit the SES initially to a two-year trial period in only three major departments and would then expand it throughout the government only if the House did not intervene. Civil Service Commission Chairman Alan K. Campbell said the administration would work to delete that restriction in conference.

Pay raises for 72,500 midlevel managers and supervisors (GS-13 to 15) that no longer would be tied to longevity in the job but would depend on performance.

Managers would have greater flexibility in firings, demotions and other personnel actions through what the Carter forces consider an stream-lined appeals process. Also for the first time, employes fighting such actions would have the right to choose between the statutory civil service appeal route and union orbitration machinery.

Federal employes' unions would have access to an independent federal labor relations authority patterned after the private sector's National Labor Relations Board.

The Civil Service Commission would be split into two bodies: the Office of Personnel Management (OPM), which would serve the president in the management of his work force and the Merit System Protections Board (MSPB), which would protect employes' rights, adjudicate their grievances against management and, along with a new special counsel, protect so-called whistle-blowers against reprisals.

Limit to $47,500 the amount that retired military personnel could earn from their combined military pension and federal salary. Because no such limit now exists, some retirees, often called "double-dippers" by critics, now collect as much as $80,000 annually.

Campbell, the Civil Service chairman, who led a White House task force in pushing for the legislation, said it was as important a milestone as the original civil service act of 1883 in that it "not only guards against spoils (political patronage) but simultaneously promotes effective and efficient management."

The results the public sees in the new system will not be automatic, Campbell said, but "will depend largely on how the president and other officials use the new tools."

Campbell said he had already reserved space at Ocean City for a four-day session in October at which several hundred managers will be invited to help plan how to put the new system to work.

The most controversial difference between the House and Senate versions to be worked out in conference will concern a section of the legislation dealing with the standard of evidence required in firings and other actions against employes, Campbell said.

The Senate requires an employe to present only "substantial" evidence against an employe in certain cases, while the House version retains the current, more difficult requirement for a "proponderance" of the evidence.

Opponents Are Listed

Following are the 10 Hose members who voted against the civil service bill yesterday:

Republicans against: John M. Ashbrook (Ohio); Mendel Davis (S.C.); Marjorie Holt (Md.); Gary Myers (Pa.); Newtown Steers (Md.); Charles H. Wilson (Calif.).

Democrats against: Herbert Harris (Va.); John Moss (Calif.); Gladys Spellman (Md.); Parren Mitchell (Md.).