The U.S. Postal Service, which once complained that it couldn't pay enough to attract and keep top executive talent, now has at least eight officials who make at least $5,000 a year more than the top pay of career bureaucrats in other federal agencies.

The two top mailmen, the Postmaster General and his deputy, earn more than members of Congress, who get $57,500 in straight salary.

Most of the upper echelon of the USPS earn anywhere from $52,500 to $61,000. The Postmaster General gets $66,000 the same as Cabinet members. Top career civil servants at the Pentagon, Justice Department, Tresury and other agencies get $47,500. That also is the top rate for political appointees at Executive Level 5 of the complicated federal salary structure.

Currently the USPS has at least 23 officials making $42,000 or more an most of them are clustered at the $47,500 level. Salary-wise, it is no longer the executive ghetto of the government.

In addition, the U.S. Postal Rate Commission, which decides the price of stamps and service standards for the USPS, has three top staff aides snaking $47,500; three commissioners earning $50,000 and a chairman who gets $52,000.

There is one vacancy on the Postal Rate Commission. Insiders hint that chairman Clyde DuPont, a former aide to Sen. Hiram Fong (R-Hawaii), will be asked by President Carter to step down to commissioner status (a $2,000 pay cut) to make room for a Democratic appointee. Odds are that David Minton, one-time staff director of the Senate Post Office-Civil Service Committee, will get the job.

Postal salaries soon may be of keen interest to members of Congress who are angered - because their constitutents are - over real and perceived cuts in service, and very real increases in the prices of stamps.

A first-class postage stamp now costs 13 cents. Postal officials have said they will have to raise that cost some time next year to 16 cents unless they can drop Saturday delivery. Going to a five-day week, they say, would mean a first-class stamp would go up "only" to about 15 cents.

Members of Congress are upset with the corporation status of the USPS because it denies them control over rates and service programs. Legislation is pending to block any cutback in a five-day delivery week.

Some influential members are talking about returning the USPS to the Cabinet, making it subject to congressional oversight and the political controls it had operated under since its beginning.

Some midmanagement postal employees also are sniping at the front office because USPS brass are fighting a court-ordered pay raise for them while top aides have gotten raises - tied to the regular civil service - of 30 and 40 per cent in one year.

Several years ago, the then Postmaster General complained to Congress that most of his top executives - who had come from private industry, chiefly the American Can Company - had taken pay cuts to serve their country. He, and many of the new postal executives, said that the financial sacrifices they made were straining their budgets, life styles and family relationships.

A spot check by this column of more than two dozen officials - taken at random - showed only one had actually taken a pay cut coming from private industry into the postal corporation. Most got increases of $5,000 or more. Congress made noises about the salary disclosures but let the matter drop. Now the new pay rates, and Hill ire over service and proposed rate increases, may start the controversy again.