It was the last long weekend of the 1970s, and across town, in a soundproof studio, a disc jockey was unreeling the Hits of the Decade, dedicating "The Letter," by Dionne Warwick, to workers inside the city Post Office.

But many of the workers were still disappointed, because they had to work the Monday before Christmas, then again on New Year's Eve. Some are scheduled to work today.

So when the dedicated "Letter" came in over the whirr of their automated, XMT-LSM multiple-letter sorting machines -- which have three-station radios and stereo headphones built into the consoles -- only a few workers were rocking to the beat.

"We just don't get no respect," complained Michele Jackson, a mail clerk for 13 years, during an interview in the Post Office snack bar, a large linoleum-floored room lined with 39 vending machines. "When the big snow came, everybody had off but us. They say with all that money they pay us we don't need nothing else. All I want to be is a plain old clerk with Sundays and Mondays off."

Thousands of letters poured into the city Post Office this weekend -- the last words of the decade. Many of the 450 "holiday" postal workers assigned to handle them had some of their own.

From her purse, Michele Jackson pulled out her last payroll stub of the year and cupped it like a love letter. "When I first came here all I wanted was $100 a week. I could've gotten over," she said. "Then they started giving me a little bit more and a little bit more until . . . Lookahere $18,988-a-year. Now I'm hooked and I can't go nowhere."

John Pryor, 55, a veteran mail clerk, took his 15-minute break. "All we have to do is get it [the mail] out," he said calmy, stating what has been an unchanging fact of Post Office life for his 37 years on the job.

Pryor, 55, has seen other things change.

"When I first came here, there was only a handful of black clerks and supervisors. Now it's all black," he said, eating collard greens out of a thermos jug.

Around him, as a soul music countdown came through Muzak-style ceiling speakers, black dock hands played Bid Whist card games in their work clothes while nattily dressed black supervisors and data technicians squared off over backgammon boards at other tables.

"Back in 1948, blacks used to get all the dirty mail," Pryor continued, wiping his fingers on his red corduroy work shirt. "You got boxes with the bottom coming out and foreign mail on those thin papers that you couldn't get a hold on -- anything to hold you back. But I survived all of that."

The Post Office went on to become the most prestigious employer of blacks in Washington, offering steady work and decent pay. Blacks with college degrees in law, medicine and education, who could not find employment elsewhere, joined the ranks of mail clerks and foremen.

"We called 'em the 'sheepskin boys,'" Pryor recalled. "Had this lawyer working right next to me on the line. Not many of those guys left now because they moved out when other opportunities opened up. But in those days it didn't make no difference. If you were a good clerk, OK?, if you did more than your share, then you could take a break, go get yourself a drink, and that would keep you going."

Although the Post Office cafeteria closed rather than admit black workers during the 1940s, the institutions's reputation for fair hiring stood the test of time. Today, while many employes complain about the monotony wrought by mechanization, most of them find solace in their salaries.

"My wife says to me, 'Why don't you quit killing yourself and stay home?'" said Pryor. "I tell her I'll survive. Besides, this is the only thing I know. I love the Post Office. We're just schizophrenic, that's all. Especially around this time of year. We are happy with the overtime, but mad at work."

Around the clock, government-colored vans, trucks and jeeps roll in and out of the cavernous Post Office building, located at Massachusetts Avenue and North Capitol Street NW, where etched into the massive Federal-style architecture is a postman's credo:

"Messenger of sympathy and love," it reads. "Servant of parted friends. Consoler of the lonely Bond of the scattered family."

Thomas Evans received his letter from the Post Office 10 years ago, in April 1970, telling him he had passed its civil service test and was hired as a clerk. He had just been discharged from U.S. Army, where he had fought in the Central Highlands of Vietnam, and had come back to The Highlands -- a low-rent housing project where he grew up in Southeast Washington.

Supervising mail delivery at the loading docks these days, Evans, who is 30, cruises the platform wearing a casual cardigan sweater, silk shirt and sports cap, with a pencil behind his ear. He commutes to work from a comfortable split-level rambler in suburban Prince George's County, where he lives with a wife and two children.

"For me, the decade has been beautiful," Evans said. "I came here as a clerk and now I'm a supervisor making $19,000 a year. Vietnam sobered me up a lot. I started taking life a lot more seriously."

"When I came home, I fell in love, got married, got a promotion and bought a house. If I have come this far in 10 years, I expect to do even better by 1990. I want to be general foreman by then. I'll be pulling in around $26,000. I'll be doing all right," Evans said.

Not far away, several younger black men wearing windbreakers, khaki slacks, knit caps and steel-toed shoes sat on the edge of the loading dock, staring out across a sea of mail bags and bins. They looked at their employer less fondly then does Evans.

"It's just a dead-end gig," said one 27-year-old Bristle-bearded man, wiping his puffy eyes with a fist. "You can't rise unless you play Uncle Tom to the white man. Who needs that?"

There was talk of the so-called "three joint lunch" that some of them say takes the edge off the monotony of slinging sacks of mail. Even a week after it was over, there was talk of The Game. "Dallas ain't s---!" one of them yells. "But the Skins can't win," his partner reminds him.

Theirs is the hard, dirty work, and in winter, they break out in a cold sweat. Icy gusts whip through the loading dock. They pull their coat collars up around their ears and get to it. Long tractor trailers back into the platform carrying millions of pieces of mail to be unloaded. Then come empty vans to be loaded and so on throughout the day.

"What does a man with a family do?" asked the 27-year-old as he lifted a sack of letters onto his back. "If slavery was still popular, we would be slaves. I'd be long gone if it wasn't for the money. Your old lady don't care what you do so long as you can pay the bills. Pretty soon, you don't care either and wind up stuck, man -- dead end."

Meanwhile, back inside the snack bar supervisor Fay Miller sat apart from the other workers.

"You know, one of the most difficult aspects of my job has been telling people they have to work these last few holidays," she said. "They all want to ring in the New Year with family and friends. And I don't blame them. But I've been around for a few years and you can bet they'll find some way to party."