When Henry Ford died, he was carried to his grave in a Cadillac hearse. A small piece of Americana, to be sure, but not without social significance. After all, the man who gave Americans mobility through the mass production of automobiles, who more than anyone else changed the look of the country in this century and who started that long national love affair between citizens and their cars, surely deserved the best even if built by a competitor. If presidents were borne to their inaugurations in Cadillac limousines, Detroit could do no less in saying farewell to old Henry. So shed a tear now for the approaching end of an era.

"We know if you want to get buried in a Cadillac hearse you better die pretty fast," says a senior executive of Cadillac, "because one of these days we're going to be out of the hearse business."

Just as, he adds, they see the big Cadillac limousine market declining, and also one of the most deeply ingrained American attitudes under assault -- that big is best, and biggest better yet. Probably nothing in our lifetime has symbolized the attitude of success being equated with size more clearly than the vision of the Cadillac. Now along with other constants of U.S. life at the end of this decade, the Cadillac too stands in a state of historic flux. It may not be an endangered species, but as a hallmark of American materialism, consumption and the unthinking expenditure of energy, the big car provides a fitting example of the country's declining fortunes and changing values as we enter the '80s.

"If you could sit in one of our planning meetings, like the one we had yesterday," says Cadillac chief engineer, Bob Templin, "you'd swear you were at the ayatollah's staff meeting. We end up shouting and screaming and pounding the table because we can't arrive at a clear consensus on a lot of these controversial issues."

"The shouting and screaming doesn't reflect any disagreement about where we're goind," says Cadillac's top marketing expert, Gordon Horseburgh, whose job it is to read American attitudes and values with at least as much accuracy as any presidential pollster. "The debate's only in terms of how you get there."

And Cadillac's chief executive officer, its general manager Edward C. Eknnard, surveys the situation facing America's luxury big car market and says: "I've heard a lot of people say this is the highest-priced crap game in the world. And it really is because the investment to do what you have to do is really incredible. If we go down, we're going to go straight over the cliff."

What they're all battling for, they say, is to preserve "the Cadillac mystique." In other words, to provide luxury with less, and yet still, as someone remarked "create that lust in a man's heart to buy our car."

These are not the best days in Detroit. Inventories are up, sales down, layoffs increasing. At General Motors, the giant of the industry, this Christmas week begins with another 41,000 workers being laid off. They join 45,000 already on indefinite furlough, and another 11,500 will go off the line indefinitely after the first of the year. Chrysler stands in danger of extinction, and the latest round of OPEC oil price increases is sending another tremor through the auto industry. Uncertainty plagues the marketplace, while inflation eats away at everyone's purchasing power and standard of living. Season of cheer it's not.

That's now how the decade began, for Detroit or the auto industry. The city had suffered during the traumas of the '60s; the race riots left the same urban tensions and problems of other metropolises, but Detroit and the corporations that make it such a bellwether of American's economic health were determined to reverse the trend of decay. The result now stands huddled against the river, in downtown, separated from the city by a freeway and surrounded by stone walls that make the tall structures look like nothing more than a modern-day fortress set off by a "moat" of moving vehicles. "Renaissance Center," as this place is called, resembles the kinds of architecture that came to typify much of the '70s: cold, impersonal cement, hanging plants placed about in an attempt to break up the heaviness, a scattering of neon lights giving the look of Los Angeles East, and everywhere a feel of plastic.

In the hotel room, the managers have installed a closed-circuit TV promotion about the center that, in its pomposity of tone and grandiose hucksterism, also says much about the '70s. Big no longer may be best, but in the attitudes that led to the building of such centers, the old yearning for large stature clearly still reigns, as you learn when you turn on that closed-circuit TV.

Announcer, solemn, portentous, voice sounding over a fanfare of trumpets and a visual scene of swirling clouds, which break to reveal, like the creation of the Earth, the towering buildings of Rennaissance Center:

The city: Detroi, Mich. It was a project that would symbolize more than just the renaissance of Detroit, but the very concept of the American city. So now, $350 million later, the first phase of their vision is complete. [Trumpets: da-daaah] The spark for the new Detroit was to be

Renaissance Center, the model of what Detroit would be like. So come with us now and stroll through this city of the future. Her is a structure of more than mere concrete, steel and glass. Here is the architectural statement of a master . . . shapes that are breathtakingly modern and timeless in their simplicity:

Elegant without being overstated. Vast without being ponderous. Rising from its heart is the Detroit Plaza, one of the tallest hotels in the world, 1,400 rooms reaching 73 stories into the sheer sky. In its core, an eight-story atrium, six expansive levels of columns, cocktail lounges, hanging gardens, causeways and a half-acre reflecting lake! . . . 760 feet in the sky, The Summit, the world's largest rooftop restaurant with a rotating dining level and a cuisine of master chefs and strolling minstrels, a rotating bar and lounge . . . .

After a while, this self-assured self-promotion becomes transfixing. You wait, wondering what superlative will top the last one. Then there comes a change of tone -- and message -- startling in its implicit recognition of other impressions of Detroit, of racial antagonisms, violence, isolation and decline.

But let's get right to the question most of you probably have been thinking but politely not asking: Why should I attend a convention in Detroit, Mich., of all places? Well, a major answer is that so many other corporations already have.Their reasons were simple: First, Detroit literally sits at the hub of this nation's transportation system . . . . Detroit, of course, more than anything else is symbolized by the automobile. The sales volume of Detroit's auto industry is greater than the national income of most of the countries in the world. In fact, Detroit's auto industry is the government's leading indicator of the economic health of the rest of the nation. Today, the empahsis is on refinement, intelligent restraint and efficiency, with no sacrifice in performance.

And it is not coincidental that these philosophical terms have rippled across the land as the new spirit of the age in every area of our life.

Again, a fanfare sounds. Clouds close over the city of the future. Minutes later, a long yellow Cadillac, new of course and properly plush, is threading its way smoothly through the freeways that connect the motor city. It's carrying me to Cadillac headquarters to help me learn about "the new spirit of the age" with its emphasis on "refinement, intelligent restraint and efficiency."

In a sense, the story of Cadillac is a part of the story of America in this century. Although we long ago entenered the atomic age with all its promise and potential terrors, for Americans this has been the century of the automobile. The car has revolutionized American life and values. It has been responsible for many of the kinds of national growth we have sustained -- of the rise of the suburbs and shopping centers, of the creation of the interstate highway system built largely with federal funds at the expense of public mass transit, of the belief in the inalienable right to individual movement, swift and free.

But it's more than these. That big luxury car hurtling down our highways, built to go fast (and speed limit be damned), crammed with pushbutton windows, stereo tape decks, cigarette lighters and other electronic gadgets represents individual power and independence. Step on it, Mac, here we come! Get out of our way, buddy, we're somebody! As a grandmother who works on the production line here says, when you drive a Cadillac "it makes you feel so happy. You're sombody important, you know."

The American worship of size and our always boasting of being the biggest in all things bespeaks, one suspects, an underlying sense of inferiority. If so, one way to compensate is to have the biggest and most powerful and prestigious car.

Over the generations the car that came to represent the pinnacle of "making it" was the Cadillac. Years ago, one of Cadillac's advertising campaigns showed an all-American boy daydreaming aloud and saying, "Some day" -- meaning, naturally, some day, if he worked hard enough, and if his efforts were properly rewarded, he'd be able to own a Cadillac. Salesmanship notwithstanding, that just about said it for many Americans.

The belief that Cadillac represents something special -- sacred, almost -- stil permeates its headquarters. Edward Kennard, the general manager, will tell you: "In talking to a lot of our owners I've had people say to me, 'Yeah, well, I'm cutting back in my business and all, but I worked hard to get where I am. I built this business and I'm going to be the last guy denied.'" Then he adds: "That's how this country got to be where it is. That's the mystique of Cadillac. That's the reward."

Through the years, the reward was a high-powered, lavishly appointed machine, gleaming with chrome, that materially set the owner apart. (In a small museum here Cadillac displays one of its old models that still stirs lust in the hearts of true automobile buffs -- a 1931 V-16 Phaeton, that weighted 6,150 pounds. Sure, it got only eight miles to the gallon, but who cared?)

Cadillac continued making bigger and bigger cars, adding long tail fins to give an even sleeker, more imperious look, and Americans kept lusting after them. The success of the small European and Japanese imports barely created a stir in Detroit. Even the Arab oil embargo in the middle of the decade -- the one event that probably signaled the most lasting impact on American life in the 1970s and beyond, and far more that Watergate or the end of the Vietnam War -- failed to force a change in attitudes about the size of cars and their relationship to fuel comsumption.

Besides, for decades Detroit had become accustomed to warnings about the imminent depletion of the world's supply of oil. From the end of World War I, and repeated every so many years, the prediction was made that the U.S. would run out of oil by the end of another decade. "That wolf call had been made so many times that nobody really believed it," recalls Bob Templin, the chief engineer.

Even if the facts indicated otherwise, many people in Detroit and in the car business nationally didn't want to believe them. They took a head-in-the-sand stance comforted by the belief that all their problems to fuel economy -- if indeed any real problems existed -- would disappear. For Cadillic particularly, the idea that small cars might be ultimately more desirable was inconceivable.

"I can assure you," Templin says, "that most executives and most sales people and dealers in luxury cars back in the early '70s had never sat in a small car or a European car -- or even seriously considered they were transportation. They were just not interested."

After Templin designed the smaller and successful Seville, the so-called "baby cadillac," a few years later, many of the old attitudes about size remained unchanged. "We had successful dealers who had been millionairs for years who still had not driven a Seville a year after it had been introduced," he says. "They kept saying, 'I'm a Broughman man, buddy,' and lit another cigar." (The Fleetwoood Brougham is the quintessence of the big Caddy.) "Mentally, they could not picture themselves in a smaller Cadillac. It was sort of an emasculation."

Now, at the end of the decade, that kind of smug assurance has gone with the gas lines.

"We see the future as being one where all the traditional givens are going to much more dificult to obtain," Templin says. "The cheap oil, of course, obviously is gone. The readily available materials are far more expensive, and of course the capacity of the world to produce materials has not grown nearly as fast. Ten years ago we didn't have to worry about how much steel we used.

"Now you no longer can say you're going to use all the steel there is, or all the glass, or all the aluminum. These have to be looked at as critical materials.Do you know that there's $50 worth of platinum in every car we're shipping out the door right now? All of our platinum comes from South Africa, and the price has tripled since 1975. And that $50 worth per car is going to double again. It's tied to the price of gold. So we're getting very very sensitive to these things. All of this says we've got to use less material per car, and we've got to be more efficient.For years we have gone on the basis that size was a criterion of value. I think we've turned around. oSize no longer is the major value. I personally feel that it has become almost a negative that people perceive."

Detroit has a term for it -- "downsizing." It's an expression that equally could apply to the country in this time of transition. The questions are, downsizing to what? And what is it that people want?

If our politics increasingly is dominated by pollsters, it's hardly surprising that our everyday lives are affected by the forces of the survey analysts. At Cadillac, no less than any major corporation, demographic trends are carefully monitored, "in depth" (naturally) attitudinal surveys are commissioned, and all the available market research surveys about American values and attitudes are bought.

Not long ago Cadillace could dray a uniform portrait of their owners. They were in their mid-50s, had high incomes, and, as they say in the market research jargon, were of "upscale" occupations and educations. And, they were males. The women who owned Cadillaces basically were wives of successful men.

"Suddenly we realized we've got a lot of young professionals out there whose incomes are growing fast," says Gordon Horsburgh, the marketing director. "They often were without children and they didn't save for a rainy day to pass on their money to anybody. They were spending now. And then we realized there were a lot of familiers beyond them whose husbands and wives work. And a bunch of hard hats and real estate people making a lot of money that you don't normally associate as people with Cadillacs."

From such material, Horsburgh, the salesman, concludes: "We've got to broaden our product array, and match our requirements. But I think we also agree we've got to hold onto that quality image dearly. It's going to be more important in the furture as we downsize our cars. We're going to make our small cars up to international standards because increasingly we're going to compete with world cars."

His research also tells him something else about Americans. "It tells you there's a growing diversity of opinion. It tells you no longer do you have this monolithic luxury car market attitude. It's exploding."

That doesn't mean doom for Detriot and Cadillac though, Horsburgh believes. Americans now are expessing a desire for customization of cars of all kinds. "People want to see themselves in it," he says. "It's the anti-mass movement. The greatest proponent of that idea, of course, is Alvin Toffler through his "Future Shock.' He'll say this is the de-massification of America. People are going back to their own individual sense of priorities because their institutions and their groupings no longer are as valid. We see this exactly in the luxury car markets. People are looking for all kinds of luxury cars, and we've got to meet their desires in the furture."

All this may sound self-evident to other Americans, but at Cadillac, it's comforting. At Cadillac, you see, they believe Americans still aspire to the best. And if the best no longer is quite so big, their lust continues to be for a Caddy. They have a point. Last year Cadillac sold 328,000 cars, the second-best year in its long history.

At Cadillac they're wrestling with a terrible decision as this year, and decade, ends. It's over what kind of car to build in 1983. Since the tooling for a new model lasts for some six years, it really means today's decision will determine what kind of car Cadillac will be at the end of the next decade.

A six-cylinder Cadillac already is in the works, but that's not the big decison. The test is to read both American tastes and dramatically changing world energy conditions and make a multibillion-dollar gamble on the size of the Cadillac in the future.

"We're in a risk business, we live in a risk world and we live risks every day," says Kennard, the top Cadillac executive. "And it would be a helluva risk if you said the car for 1989 might be too big a chance for the Cadillac driver. What does that guy traditionally perceive the Cadillac to be?"

Kennard belives he's got at least part of the answer. "I don't believe the love affair with the car is over. It's just that you have to build what he wants. The guy who builds that product is gonna get richly rewarded. That guy isn't going to give this up. That's going to be one of the last things he gives up."

Despite the lessons of the decade that size and overconsumption can lead to economic disaster, Detroit still thinks big.

Down on the line, Kenny Lavinski was watching the new Caddys roll off, one after the other, in endless procession. They come equipped with a new digital electronic fuel injection system, something the Cadillac people say is a "direct result of space-age technology." These cars have a "self-monitoring, self-diagnosing" system.

Kenny was indulging in a bit of self-diagnosis himself. He's been at Cadillac 15 years. The day of the big car is over, he says. Then:

"You know, 10 years ago I had the world by the tail. Now the world's got me."

Without realizing it, Kenny had just delivered an epitaph for a decade.