If Marshall McLuhan and Florenz Ziegfeld got together, they might come up with something like The Ford Motor Company's 75th anniversary special, "A Salute to the American Imagination." This is meant as a compliment. Indeed, it is meant as the highest compliment for a program that gives much-needed new life and credibility to the phrase "the magic of television."

The two-hour, $2-million production, at 8 tonight on CBS (Channel 9), is fantastic, bombastic, spectacular and intimate in ingenious and resourceful ways. It represents a personal triumph for 33-year-old producer Steve Pouliot, who spent the past year putting it together and who has a welcome and obvious virtuouso's affection for TV.

Ostentatiousness is in the air, all right, as it inevitably would be when a big corporation decides to pour on the bucks for a self-commemoration. But with few lapses, Pouliot, director Don Mischer and writer Rod Warren maintain a tone of friendly, affecting pompousness rather than the kind of clunky, campy cant that marked and ruined last week's General Electric 100th birthday show on ABC.

There is all the difference in the world between the two programs and that difference has to do with taste, class and discretion. Pouliot displays an abundance of all three, so that even a program featuring megaton production numbers and a parade of stars seldom seems gross or garish.

The stars include not only the likes of Paul Newman, Joanne Woodward, Telly Savalas, and Madeline Kahn, but also playwrights Tennessee Williams, Neil Simon and Arthur Miller who each introduce a scene from one of their works.

An interlude from "The Glass Menagerie," with Ronee Blakely and a mercifully subdued John Ritter, doesn't quite work, but it is worth tolerating for Williams' own introductory remarks in his gravelly and insinuating Cheshire-cat growl he quotes himself beguilingly; "Yes, I have tricks in my pocket I have tricks up my sleeve . . . I hope to give you truth in the pleasant disguise of illusion."

Simon introduces a scene from "The Prisoner of Second Avenue." one of his feebler asides on modern urban blues, and Miller a moment from "Death of a Salesman," which is rewarding not only for the impromptu poignance of Edward Asner's Willy Loman but also for the way it blends into a performance of "That Lucky Old Sun" by Ray Charles. This is in fact one of the most heavenly and affecting dissolves in television memory. Producer Pouliot has such love for his work and the medium that he subliminally convinces you one's sleeve is the proper place to wear one's heart.

Interspersed with the entertainment are person-on-the-street interviews filmed by Michael Travis and featuring American folk who speak in convincingly upheat tones about their lives and their work - like the New York taxi driver who declares. "This is the cleanest cab in the world."

Pouliot displays a showmanship that successfully transforms the grandose into palatable television terms The program's finale has a 30-foot repica of the Statue of Liberty rising out of the stage as comfortably and innocently as it might have in the heyday of Radio City Music Hall. Appropriately, Ethel Merman is given domain over the program's most determined show-stopper, a performance of "Before the Parade Passes By" (from "Hello, Dolly") that involves 250 extras, a 20-foot electrified Chinese dragon, and a monsoon of fireworks.

Pontification is kept to a minimum; writer Warren daringly avoided the erstwhile momentousness that usually afflicts such scripts there's none of that "American was happy." "America was sad," "America had a bad case of the hiccups" nonsense. Of course, Ford did foot the bil, so one can't blame them, especially considering all the recent bad Pinto publicity, for having Savalas note that it is "part of our national creed to believe that next year's model will be better."

Among other contributions to the program so striking that they cannot be overlooked are the sets designed by Charles Lisanby and the occasionally witty choreography of Mike Hoover, blessedly disco-free for the most part.

Throughout the program a black-tie audience at the Ambassador College auditorium in Pasadena is seen applauding approvingly. In fact, less than half the program was taped in front of that audience; it's a prop, edited in at appropriate juncutres. But this seems not just casual TV manipulation, under the circumstances, but rather an exercise in the wizardry of videotape illusion. It is probably no more deviously deceptive than those shots of theater audiences clapping their little mitts off that always followed Busby Berkeley musical numbers which wouldn't have fit on any theater stage smaller than the Grand Canyon.

Twenty-five years ago, television stopped in time for Ford's 50th anniversary show, telecast on two networks at once and produced live by Leland Heyward. The program was a masterpiece then and it has since taken on the added attributes of both legend and time capsule. A glimpse of it is seen on the 75th anniversary show.

Air time should be made for such classic programs on public television; Ford could underwrite the cost of clearing all the rights and public TV would be an ideal showcase for broadcasts that time has turned into either works of art or historical artifacts or both.

But Pouliot has followed the unfollowable act with enviable flare and invention; he has pushed the existing technology to its limits and done it with a sense of wonder and terriby contagious pleasure. He was aiming for a milestone and he achieved it, but "Imagination" is a milestone in the least pretentious and most enjoyable of ways. It is one of the rare television events worth building an evening around, and we'll be lucky to see anything to equal it for months to come.