Eat your heart out, John Travolta.

The genuine, irresistible urban cowby has suddenly appeared in the magnificent, oversized presence of Meat Loaf as the resourceful and endearing young hero of a delightful new comedy, "Roadie."

An unheralded opener at area theaters last weekend, "Roadie" is a rollicking comic sensation waiting to be discovered by fun-loving moviegoers. And they'd better act fast: It may be pulled pronto.

A native Texan, Meat Loaf is famous as a rock vocalist. Before that, he was a stage actor in New York, where his credits included "Hair," "The National Lampoon Show," and Joseph Papp's productions of "As You Like It" and "Othello." His brief film appearances in "The Rocky Horror Picture Show" and "Scavenger Hunt" wouldn't have prepared one for the astute and rousing performance that dominates "Roadie," but it's obvious that Meat Loaf perfected a whale of a film-acting technique somewhere along the line.

He plays Travis W. Redfish, an apparent slob of a country boy whose scowl, bullish physique and flowing mane are merely superficial aspects of a fundamentally decent-indeed adorable -- character. He drives a beer truck in partnership with his buddy B. B. Muldoon (a corpulent original in his own right, played by Gailard Sartain) and resides with his sedentary dad, Corpus C. Redfish (Art Carney) and stringbean sister Annie Poo (Rhonda Bates), B. B.'s intended, on a spread near Austin.

The Redfish family trade is salvage, and Corpus' home is a Rube Goldberg wonderland cluttered with gadgets: Corpus rarely moves from a favorite chair mounted on a motorized platform; and when Annie Poo comes through with the vacuum cleaner, she routinely sucks the dust off Pa.

"Roadie" depicts Travis' misadventures after he impulsively joins a touring rock show and encounters a strange new subculture. The impulse is love at first sight. While passing a disabled van, he is dumbstruck by the supplicating smile of a girl at the rear window. He stops, offers help, and meets an ingenuous flake who calls herself Lola Bouillabaisse and boasts, "I'm a groupie on my way to New York City to be the greatest groupie that ever lived. Rock n' roll is the greatest source of energy in the world, and groupies are the spark plugs of rock 'n' roll."

Despite appearances, Lola, a teenage runaway from Tulsa (played by newcomer Kaki Hunter, a 25-year-old native of Silver Spring), is as virginal as she is naive. While not averse to bestrowing her favors on a rock star, she insists that it be her idol of idols, Alice Cooper. (Travis, a country & western type, astounds her by making a wild guess that Cooper must be "one of Charlie's Angels.")

Travis and Lola are absurdly attracted and obviously meant for each other. For love of Lola, Travis repairs the van, drives it to Austin and installs the sound equipment for a scheduled performance at the Soap Creed Saloon by Hank Williams Jr., averting a possible cancellation and riot by virtue of his fantastic mechanical aptitude. At Lola's urging, Travis stays on as a "roadie" -- the jack-of-all-trades driver, mechanic and gofer of the company -- and rapidly becomes a legend:

When an Idaho municipality cuts the power on a concert headlined by Blondie, Travis builds a homemade generator powered by cow manure. When a weirdo group in Los Angeles refuses to perform because Lola has lost its ration of cocaine, the incensed Travis herds the band on stage like a furious sheepdog.

Though basically good-natured, he is capable of inflicting considerable damage when riled. During one of the funniest slapstick scenes in recent memory, Travis is forced to butt heads with an equally beefy customer at the Soap Creek Saloon. The sight of these bar-room behemoths snorting, pawing the dance floor, charging and then bashing skulls is a classic tall-tale situation realized in a modern setting. There's a comic bonus: The concussion leaves Travis in a slightly deranged mental state known as "brainlock," which causes him to free-associate brilliantly and drive like a maniac until time and massive quantities of beer bring relief. a

Travis is the invention of a Texas journalist called Big Boy Medlin, who created the character for a sports column in the weekly Austin Sun, and sustained him after moving to Los Angeles and writing for the L.A. Free Press and L.A. Weekly.Michael Ventura, a native New Yorker, became a colleague and friend of Medlin's in Austin. They began collaborating in L.A. and "Roadie" is the first of their original screenplays to be filmed. It appears to offer Hollywood the most promising comedy-writing team since Paul Mazursky and Larry Tucker broke through with "I Love You, Alice B. Toklas."

"Roadie" draws on recent films like "Smokey and the Bandit," "Up in Smoke," "Citizens Band" and "Phantom of the Paradise." But it's a tangy new synthesis of regional and colloquial and topical humor, lively characterization, rowdy slapstick and offbeat romance. It has been expertly directed by Alan Rudolph, whose pictorial and technical finesse serve this exuberant material far better than they served his previous credits, "Welcome to L.A." and "Remember My Name."

Travis' cross-country infatuation with Lola reaches a climax in New York. Exasperated by her fixation on Alice Cooper, Travis arranges a meeting with Cooper himself, whose imminent Madison Square Garden concert is sorely in need of a mechanical genius. How will Lola react near her favorite rocker? Travis hopes she'll come to her senses, wherever they are, but it's possible that Lola can imagine no destiny sweeter than idolizing Cooper.

In the improbable romance between fat, stable Travis and petite, starstruck Lola, the writers achieve a remarkable teetery balance between poignant and farcical elements, a trick that eluded Robert Altman in "Brewster McCloud." The prevailing tone is friendly and expansive. "Roadie" seems eager to find common humorous ground, to reconcile the cultural extremes that separate Travis Redfish and Alice Cooper, to unite a vast cross-section of the public with an entertainment that excels at both homespun and hip varieties of comedy.

One element defied amusing integration: the musicians of the rock group Blondie. Vocalist Deborah Harry is an exception; she does take to the camera and the genial mood. But her cronies in the band prove incorrigibly sleazy. Their tackiness isn't humorously stylized, like the unwholesome aspects of the other rock bands that figure in the plot.

Kaki Hunter's performance is a little wobbly. She's inclined to overdo it when purring Lola's more insinuating or ingenuous lines. She seems more comfortable and appealing when the groupie facade slips and Lola is caught in uncertain, silent moments, suddenly feeling confused or apprehensive.

Above all else, there is Meat Loaf. I doubt if any stout funnyman since Fatty Arbuckle has proved as adept at imposing a commanding yet agreeable identity on the screen. Meat Loaf's Travis seems a more impressive feat and appealing character than John Belushi's Bluto in "Animal House." In addition to sustaining an unconventional romantic lead, Meat Loaf displays a range that extends from boyish charm and gentlemanly gallantry to bellowing, stampeding, demonic zaniness. Like Belushi, he knows how to move his bulk gracefully. He's also blessed with wickedly funny eyes -- the dark irises swivel and dart across slightly protruding whites with devastating comic alacrity.

Judging from the negligent release, United Artists hasn't the slightest idea of what a powerhouse performance and winning vehicle they've got to brag about. A joy to behold and listen to, Meat Loaf is an apparent grotesque who emerges as a prince of a guy.

He justifies Corpus' admiring description of Travis: "We never had to do much about that boy, and he always knew how to lighten up a dark situation." d