OUT of the flood of first novels being published this fall, two seem to have a special handle on the nature of families - how they both nurture and fail their young, and how the process of working through family influences to forge one's own identity often can be painful.That's not to say the process is without humor. In Peter Hedges's first novel, "What's Eating Gilbert Grape," Gilbert Grape seems to be a cross between Eddie Haskel (of "Leave to Beaver" TV fame) and James Dean. The town he lives in is both Iowa hamlet and "Twin Peaks." In this off-center universe, people are alternately cynical and sweet, real and cartoonish. But to Hedges's credit, it all works. Gilbert is a young man who doesn't know where he wants to go, but clearly it's away from his family and the town. His mother, Bonnie Grape, started eating after her husband's suicide 17 years ago, and never quit. She's so fat the floor beneath her chair is close to caving in. His younger sister, Ellen, is as ferociously self-absorbed as a born-again Christian as she is as a couch potato with perfect nails. Arnie, 17, who is retarded and climbs the local water tower when he gets mad, has outlived all medical predictions for him. Amy, Gilbert's much older sister, waits on Bonnie, holds the family together, and in the process is turning into an Elvis-loving old maid. Amy and Gilbert spend much of their time shoring up the family - not to mention the floor under their mother. This is one comically dysfunctional family. So is their town, Endora, Iowa, (pop. 1,091), where the opening of a Burger Barn and the return of a town-boy-turned-TV-announcer are awaited with downright reverence. Hedges, a native of West Des Moines, has a perceptive grasp of what it's like to grow up as an outsider in a small town. He has some sharp observations about the hypocrisy of respected town denizens who look down on the Grapes, yet who, in private, carry on in most disrespectful ways. The plot barrels toward Arnie's long-awaited birthday party, one he was predicted never to see. Two older siblings return home and disrupt the Grapes' fragile coexistence. Another family tragedy leads to a surprising act of unity among the siblings. There are many surprises in this book - it sparkles with fresh facets of character, turns of phrase, and situations. Hedges's gifts for multifaceted characterization, spontaneous dialogue, and surprise make him someone to watch in the future. In Brian Morton's "The Dylanist," the main character of Sally Burke has the opposite kind of family: They're wonderful. But for other reasons, she doesn't fit in, either. In this first novel, Sally's father, known as Burke, is a famous labor organizer. He's an undemonstrative man, but Sally has learned to read his signs and she feels loved. Her mother, Hannah, is an emotional and opinionated schoolteacher. The parents' life together is filled with political passion, which creates a larger framework. Next to them, Sally feels unfocused, pale, "roadless." Her tack is to disassociate herself from causes, to become, as a friend puts it, a Dylanist, "immersed in her own feelings." Like Bob Dylan, she was "a romantic about love, a cynic about everything else." "The Dylanist" takes Sally from childhood to her early 20s, through friendships with girls, a comfortable but stultifying relationship with the puppyish Owen, another with a strong man who also stultifies her with too much gentleness. If "Gilbert Grape" is all primary colors and circus music, "The Dylanist" is rather mauve and adagio-like. Sally's life, that of a woman who can't find herself, could be boring. But it's not, because of Morton's lovingly drawn, carefully realized portraits. He's great on youth's absolute conviction and ability to change: Sally is sure that her parents' decision to move to a huge old house after retirement will kill her father. But, turn the page, and Sally's talking about how well her father took to it, much to her surprise.