The precarious reputation of ABC News takes a great leap upward tonight with the telecast of "ABC News Close-Up - Youth Terror: The View from Behind the Gun," and explosive, important and uncommonly immediate look at juvenile crime in the big city of the '70s.

Pam Hill, new executive producer of the "Close-Up" series, and Helen Whitney, who wrote, edited and directed this report, have turned a sociological cliche into a riveting and profoundly distrubing television reality. They elected to let the kids tell their own story, without interference from narrator or on-camera reporter. This technique might not be appicable in all documentary situations, but here it works brilliantly and with great impact.

Unfortunately, the report is so powerful that a dozen ABC affiliates are expected not to carry it (it will be seen as scheduled in Washington on Channel 7 at 10), while others may delay it to later time periods, even though ABC has scheduled a follow-up 90-minute discussion for 11:30. "Youth Terror) Is There An Answer?" will feature some of the experts and authorities who were so wisely omitted from the program itself.

The reason some affiliates dropped out - and by refusing the program, they are effectively turning their backs on the problems it confronts so graphically - is the use of strong language by some of the participants. They are street kids and they use street talks. Their vocabulary includes, fleetingly but audibly, words and expressions not previously heard on a schedule commerical network prime-time program.

Two or three of these words are on the list of the "Seven Dirty Words" spoken by comic George Carlin on a record album played by a New York radio station. A single listener objected to the broadcast, sued, and the case is now befor the Supreme Court, where it may become part of the Court's current campaign to rewrite the First Amendment.

Most of the stations which have indicated they will not carry "Youth Terror" are located in the South. Three are in Texas. At WFAA in Dallas, General Manager Ward L. Huey insisted yesterday he would not air the program unless the rough language was edited out.

"We simply are most seriously concerned about profanity on television and this violates our politics," Huey said.

The program bas been recommended by the National Education Association and praised in a publication of the National Council of Churches. Asked if he didn't think the seriousness and relevance of the subject matter justified bending the rules, Huey replied, "No."

ABC has ruled against profane and obscene language on the air as well, but producer Hill said from New York that the decision to make an exception for this exceptional program came from the highest corporate levels at ABC - from ABC Television President Frederick S. Pierce, ABC Inc. President Elton H. Rule, and ABC Inc. Chairman Leonard H. Goldenson, all of whom saw and approved the program.

"The language is part of the lifestyle of these kids, " Hill said. "It's an expression of their age, really. To edit it out would be limit that expression. It's indigenous to them; it is part of their world view."

A dozen chicken-hearted affiliates may not seriously diminish the impact of the program, however, since it will be seen in most of the large urban areas of the country where its subject is most crucial.

It is shocking to hear those four-letter words on television, but much of what these teen-agers say about themselves and their view of life is shocking even when it is not profane. Sometimes they talk as if their dialogue had been written by a socially conscious Hollywood scriptwriter: "Don't tell me crime don't pay, 'cause it does"; "This is a concentration camp, this is hell"; "You can't just ignore us, 'cause we exist . . . so why not give us a chance?"

The film opens with a startling image - a "Brooklyn youth" wielding a handgun and declaring, "This gun talks . . . This is what talks around this neighborhood." Later he brags about the number of crimes he has committed. "I alone have cost this city tens of thousands of dollars," he says.

During the monologue, the boy stands on a Brooklyn roof where he is commandant of a squadron of piegons he keeps there. The director cuts to shots of the soaring piegons - the boy's link to vicarious freedom - as he speaks of "breaking heads" and being "the boss." Whitney's editing of this segment is unerring and elegant; the juxtapositions are sublime and penetrating.

Hill started the project and then, when she was appointed "CLose-Up" executive producer, turned it over to Whitney, who spent four months getting to know the kids before the camera crew came in. Since much of what they do on the street is to them a kind of theater anyway, they did not noticeably alter their behavior for ABC News, although after one outburst, one of the kids told Hill, "Maybe I shouldn't use that language, "cause you won't be able to put it on television."

Though Whitney thought she's won the confidence of most of the residents, her purse was stolen while she was filming in a New Jersey slum, and very early in the program, viewers will see a woman shoved onto the hood of a parked car during a street scuffle. That woman was Whitney.

She was asked if the presence of cameras might have actually incited some of the violence that is seen in the film, and why the crew didn't try to stop the fights that were shot. "We were in the process of getting a story," as opposed to intervening in a story," Whitney said. "These were minor outbreaks of random violence which we saw occuring whether our cameras were on or not. I think if we had gotten involved in them, they might have become very much worse. Besides, there was very fes of us (five) and a lot of them."

The hour has its side effects. It really puts the lie to the Tv image of the American inner city as put forth in such fraudulent entertainment programs as "Good Times," "Chico and the Man," "Stanford and Son," and numerous cop shows like "Starsky and Hutch." They don't begin to convey the despair, the deep and hopeless cynicism, or the curious brotherhood of victimization that actually exists. There are nothing but victims in this report - even the big shot with the gun seems, finally, pathetic and abandoned.

"It's a question about the have's and the have-not's" says one kid, contemplating the elusiveness of the American Dream. "What's a dream to you, is a nightmare to me."

Even when what they say is self-serving or self-glorifying, it can be alarming and revealing.

Hill decided from the inception of this project that the report would be in what ABC calls "non-narrative" form - modified cinema verite, with no narration - and she cites such inspirations as Frederick Wiseman and Marcel Ophuls. There is television precedent as well; some of the best pieces on Reuven Frank's "Weekend" show, on NBC, have been stories that told themselves.

Ironically, an NBC News documentary scheduled opposite the ABC special tonight - "NBC Reports: Escape From Madness" - suffers from the very impediments to communication that Hill and Whitney took pains to avoid. The hour-long report, at 10 on Channel 4, seems to further obfuscate it subject with each additional attempt at illumination.

Though capably narrated by Tom Snyder, the program seems the very enemy of clarity. It never fully explains to viewers the difference between neurosis and psychosis, spends itf first quarter on a superficial psychological biography of singer Rosemary Cloonery, and appears to be continually repeating introductions to topics rather than dezling with the topics themselves.

Producer Earl Ubell co-wrote the script with Snyder and it is a confusing botch; inserted re-enactments of actual events and lurid attempts to dramatize the symptons of psychosis lack dignity and coherence. The program opens with images of madness straight out of "The Exorcist."

NBC News is considered a more "respectable" shop than ABC News, so it's surprising to see the tables turned tonight - ABC with the class act and NBC with the carnival.

There is a temptation to theorize that the "Close-Up" shows how journalist at ABC News can flourish when news boss Roone Arledge keeps his mitts off their work; some of the worst things on the first "20/20" were Arledge inspirations.

But Whitney said, 'Roone gave us a completely free hand and nothing but encouragement" and Hill said, "Roone was always supportive." Knowing when not to meddle is one sign of executive smarts; the credit for "Youth Terror" might as well be passed around, because it is a striking and auspicious achievement.