The Reagan administration will be able to fill about 6,000 top federal jobs, more than half of them carrying $50,000-a-year salaries, when it takes office in January. That is more than double the number of jobs available to any incoming president in modern times, and about twice as many positions as the GOP transition team thought it would have available to help put the new chief executive's mark on the federal bureaucracy.

Between 2,700 and 3,000 of the jobs are in the so-called Schedule C category. It is used to designate political, policy or confidential slots that may be filled by the new president of his designee outside of regular merit system procedures. The jobs pay from $20,000 to $50,000 and include everything from special assistants and private secretaries to chauffeurs and chefs for cabinet officers. A listing of those jobs, who is in them and where they are located will be published in the Plum Book. It will be in the hands of the administration -- and at Government Printing Office bookstores in limited quantities -- some time in the next couple of weeks.

In addition to the clearly identified Schedule C jobs that routinely change hands when a new political party takes control of the White House, Reagan will also be able to fill about 1,000 "non-career" vacancies in the Senior Executive Service. Most pay $50,112.50 per annum.

Besides the noncareer SES vacancies that Reagan will have available he will be able to select people to fill 2,000 current vacancies in the "career" side of the SES. Those slots can be filled via promotion from government, or by outsiders.

Ironically, the extraordinarily large number of jobs available to the Republicans are the result of President Carter's Civil Service Reform Act. It created the gradeless, superelite SES corps by taking in most of the old "supergrade" (Grade 16, 17 and 18) jobs in government. In total there are 10,777 executive-level jobs in government. About 9,800 of them are in the SES.

Under the Civil Service Reform Act, the executive service is 90 percent "career" and 10 percent "noncareer". The law says that no agency may have more than 25 percent of its SES filled by noncareer executives.

Since the SES is relatively new and has never undergone a change of administrations, nobody is sure how the procedures set down by law and on paper will work in flesh-and-blood terms.But the large number of career and political job vacancies available to the Reagan people should comfort both bureaucrats and incoming politicians. The new team will have a very large number of jobs to fill so they can get the government moving in the direction they want it to move without looking for ways to purge the career executive ranks immediately. An estimated 80 percent of top jobs are in the metro Washington area.

Tomorrow: A sneak preview of what the Reagan administration can, and cannot, do with the "career" SES!