With the 1984 election getting close, watch for the Reagan administration to put on a happy face for its federal family and muzzle--or drop--officials who do anything to anger or frighten one of the nation's largest minority groups, the 6.4 million active and retired federal and military personnel.

Reagan officials are impressed by that number. All of those folks are old enough to vote! And the feds, especially retirees, make up a sizable chunk of the people who actually vote in key industrial and Sunbelt states.

The numbers are impressive, particularly if you crank in spouses and children, and they impressed the Jimmy Carter reelection people who first worked up the figures.

For example, during the first eight months of 1980, Carter aides repeatedly said federal workers would be lucky to get any raise because Carter mistrusted the system the federal government uses to measure comparable pay rates in the private sector. But after the U.S. voter bloc figures were shown to the president, the data seemed more reliable. Carter approved a near-record 9.1 percent pay raise for the feds, just one month before the election.

If political planners get their way, President Reagan will propose a 4 percent raise for next April, but settle for an earlier date if Congress pushes the matter. Planners will also recommend that the administration seek a face-saving compromise with Congress over the administration's controversial proposals to revamp the government's seniority-based personnel system to base pay raises and job security on performance. Many Reagan administration officials think the president can once again capture a sizable chunk of the federal worker-retiree vote if the economy keeps on improving, and they benefit from it.

Insiders say that most key political appointees involved with federal pay and policy matters have decided it would be foolish to keep butting heads with Congress over the performance proposal. And they also think it would be wise if the administration cooperated with Congress on a federal pay raise rather than sticking to its earlier plan to freeze such pay until October 1984.

"A lot of people in the White House and at the OMB Office of Management and Budget think that Don Devine has become a political liability," an administration official said. Devine heads the Office of Personnel Management has led the administration charge to reduce federal health insurance costs, and alter the personnel system to give managers greater authority to reward or punish employes.

A former OPM official said that during the first half of Reagan's administration, "Devine did exactly what they wanted him to do. But he is abrasive and he ticked off Congress. . . and the kind of people you want in an administration are not necessarily the kind you want when you are running a campaign."

President Reagan clearly favors the performance proposal. And he (along with the OMB) would like to save as much as possible by cutting or delaying the size of the next federal pay raise, since each 1 percent increase costs about $700 million.

But Congress has made it clear it doesn't like the federal job plan, and the first budget resolution approved by Congress called for a 4 percent federal pay raise this January.