With NBC's telecast of "The Godfather" and "The Godfather, Part II" in considerably more than their entireties, the network redeems the word "event" after having systematically besmirched it in months past.

"Godfather" in fact represents the most satisfying and significant television event since "Roots."

"Mario Puzo's 'The Godfather': The complete Novel for Television" will take nine hours of air time and four successive nights, starting tonight at 9 o'clock on Channel 4 to reach its conclusion. But when it's over, viewers who see it will all feel the sense of accomplishment one gets from making it through an epic - in this ease, and epic of depth, intelligence and shattering emotional peaks.

It's the kind of satisfaction that residents of print centuries ago must have felt after reading a long and rewarding novel, or the way those who still fancy themselves members of a reading generation feel even today. Beyond its surface explorations into heritage, gangsterism, violence, moral relativity, codes of honor and rites of passage. "The Godfather" as television brings us into harrowing confrontation with human nature.

This is something television very rarely does, but when it happens, as with "The Godfather," it casts doubt on TV's reputation as the enemy of literacy.

Literature cannot be the enemy of literacy.

It took two years to edit together "The Godfather" and "The Godfather Part II." both of which won Oscars as Best Pictures of their years (1972 and 1974) into the TV epic that starts with a two-hour chapter tonight and ends with a three-hour installment Tuesday night. In the course of this transformation, about an hour's worth of footage that had been cut for theatrical release was restored, and "Part II" was substantially restructured.

Barry Malkin, under the supervision of director and co-writer Francix Ford Copples, edited the film so that the story now flowos chronologically from just after the turn of the century, when young Vito Corleone, to the late '50s, when Vito's son has inherited his father's empire of crime.

The effect of the new editing upon the two films turns out to be the best that could be hoped for; the first "Godfather" film, the stronger of the two, has not been harmed by it and the second "Godfather" film has greatly benefited from it. Originally, the early and late, sequences alternated as flash-backs and flash-forwards in the second film; now the early sequences form a prologue to "The Godfather" and the sequences from the '50s better sustain the narrative momemtum, although it is still clear that the original "Godfather" movie is superior.

That film will just begins as tonight's episode ends: Marlon Brando as the Godfather is introduces soon after we hear the original film's opening line, "I believe in America."

Among the scenes that don't seem to have been in "Godfather II" when shown in theaters is one in which Vito as a boy meets another lad whom he dubs Hyman Rothstein. "Hyman Roth," as he is later known, won't appear again for a couple of nights, and many years to come, when he returns in old age as a gangster enemy of Vito's son, Michael.

Additional new scenes tonight include's couple of murders committed by Vito after he has returned to his native Sicily to search for the man who ordered the killing of his mother years before. The additional killings add nothing but time to the story; in addition, the stabbing of the old man Vito searches out has been edited for violence so that it now lacks impact.

It says something about TV mentality, particularly that NBC's zealous censor Herminio Traviesas, that it is okay to add new, gratuitous killings, (so long as they aren't too explicit) even though they do nothing to further the story, while a murder that is erucial to the plot and the development of Vito's character has been trimmed.

Of course this is a violent story, but the acts of violence never seem the cheap thrills that punctuate the typical TV cop show. The violence is grim, sobering, devastating.

The other major controversial aspect of the "Godfather" films is that they portray Italian-Americans in only one light - a negative one, despite admirable traits shown by many of the plaints over all this TV time going to what could be interpreted as a protracted slur. Coppola's sister, Talia Shire, who plays Vito's daughter in the film, will make a brief on-camera statement before the program starts tonight.

The statement includes the disclaimer that the film "details the frightening actions of a small criminal characters. To quell possible com-group, and it would be grossly unfair to let these characters and their story represent the history or the deeds of Italians and Italian-Americans. This is not the story of an entire people . . ."

Perhaps the quality of the original films most endangered by the transfer to TV was their rich texture, both visual and spiritual. The somber shadows and silhouettes of the opening sequences set in New York in 1918 are a problem on television; the eye is uncomfortable with them, although advertisers will probably be delighted tto see how their overlit commercials stand out like fairies on a lawn.

But we become accustomed to this heavy dark look and, with Brando's first appearance, the film perks up considerably in compensating energy and urgency. None of the acting suffers from the reduction to TV size. If anything, Al Pacino, Robert De Niro, James Caan, Richard Casterllano, Robert Duvall, John Cazale, Shire and all the others seem more immediate and admirable than ever.

The large-scale family rituals - birthday, baptism, wedding, funeral - hold up because of the skilful editing. Details of exposition are handled with such skill that one never finds oneself in doubt about time or place forvery long, despite the scope of the story and the number of years leaped. Added scenes from "Part II" help make the Pacino character more interesting after the Don dies (late Monday night): while Brando dominates the whole nine hours, even though he appears through only about four of them. Pacino's methodically repressed person seems much more expressive and convicting within the confines of the TV image than it did on the theater screen.

Much more time and money went into the "Godfather" films, and mucch more care into the reediting, than is usually expended on television programs, so strict comparison with average TV fare is unfair. And yet to see images so suffused with meaning and impact, to experience a story so sweeping, so enthralling, and so heart-breaking, is to realize again that there are magnificant possiblities in television that rarely get explored.

"The Godfather" in its new incarnation proves to be the kind of intimate epic that television is best equipped to convey. It does require a commitment of time and concentration, but this turns out to be a pretty refreshing demand, since most of what trots across the TV screen is easy, lazy or silly.

One hopes hat a nation hooked on junk food will accept the feast that NBC is about to offer. The new "Godfather" proves entirely deserving of four more nights of our lives.