Congress soon will be asked to okay a White House plan that would completely revamp the system Uncle Sam uses to hire, pay, promote, transfer and fire middle and top management bureaucrats.

Many of the 81,000 federal workers in career and political jobs from Grade 14 to Cabinet rank would be involved in the new EMS (Executive Management Service). Details of the plan were outlined here July 28. Federal officials say that a legislative package setting up the EMS will go to Congress early next month. President Carter will give strong support to the EMS, which he views as the key to his reorganization of the "people" side of the government.

Under the EMS, most "management" employees in government making $28,725 and above would be shifted to the new system, which gives agencies greater authority to transfer and reassign workers. A rank-in-man (or woman) system similar to the military and Foreign Service would be set up so that employees would carry grades with them into various assignments instead of having grade determined by the size of programs or the number of workers supervised.

Veterans' preference would not be part of the EMS, and agencies would do their own recruiting and hiring of new executives. The number of "non-competitive" or political-type jobs would be increased in the EMS, and officials say that career and noncareer employees would be interchangeable, with managers being assigned wihere they could best be utilized without regard to their job status.

Although the new EMS apparently will not include the controversial proposal putting managers under three-year contracts to agencies - which many White House aides favor - indications are that agencies would be tougher on workers who are considered "marginal." Employees who refused geographic assignments would be on shaky ground. They would, however, be guaranteed "fallback" rights, meaning that they could be returned to jobs and positions outside the EMS.

Although officials aren't saying what new "benefits" would be provided the managers as a trade-off for security, there are plans to ask Congress for certain financial incentives for EMS members.

The EMS would include "management" types in Grade 14, which has 51,000 workers; GS 15, with 25,000; Grade 16 which has 3,361 and employees in Grades 17, 18 and up through the five political executive level positions. Since Washington is headquarters for most agencies affected by the plan, a significant proportion of workers taken into the EMS would be here.

Officials expect there will be some opposition from potential EMS personnel who are especially nervous about the greater emphasis on mobility. They fear that bostes - as happens in government and industry - could use "exile" type assignments as a device to force employees to quit.

Top brass who have worked on the EMS concede there is no way to guarantee an effective management system where a vindictive boss would not on occasion, abuse his or her greater authority. They feel, however, that the top-drawer management Carter says he wants in government means that agency heads must have greater say-so over who works for them, and where.

The Nixon administration tried to get a somewhat similar system - called the Federal Executive Service - through Congress years ago. The Democratic majority balked at it, fearing that the Republican White House would use, and abuse, the FES to politicize the civil service.

Insiders believe the EMS has a better chance of becoming law because it makes fewer changes in tenure than the Nixon proposal, and also because Carter - not Nixon - will be making it to a Democratic dominated House and Senate.