Aug. 8 (Bloomberg) -- Cadillac's biggest sedans, once a symbol of the American dream, are in danger of joining Elvis Presley and tail fins in the pop-icon obituary column.

Plans are on hold for new versions of the largest Caddies, which trace their lineage to the 1950s-era car so beloved by Johnny Cash's fictional factory worker in ``One Piece at a Time'' that he smuggled one out part by part. General Motors Corp. has sidelined replacements for the Cadillac DTS and STS in favor of more fuel-efficient models, people familiar with the plans said.

``In the bad ol' days, the big old Caddy and the big Buicks were the way you showed you'd made it,'' said Alan Baum, director of forecasting at the auto consulting firm Planning Edge in Birmingham, Michigan. ``To the extent people still want Cadillacs, they want a very different car.''

GM is rethinking a brand that captured the imaginations of pioneer rocker Chuck Berry in ``Maybelline'' and the face- painted group Kiss in ``Cadillac Dreams.'' Chief Executive Officer Rick Wagoner is de-emphasizing fuel-hungry models and accelerating those that use less gasoline or none at all. He already suggested selling the Hummer line and delayed new large pickups and SUVs.

``It's the absolute right thing to do right now,'' said John Wolkonowicz, an analyst at Lexington, Massachusetts-based Global Insight Inc., whose hobby is automotive history. ``They have to build the models that a high volume of customers want to buy right now.''

About 1,500 workers build the DTS at the GM Hamtramck, Michigan, factory that has produced Cadillac models since 1985. The plant is scheduled to switch over to the hybrid-electric, plug-in Chevrolet Volt in 2010. GM isn't commenting on what will happen to DTS assembly. The STS is built with other Cadillacs in Lansing, Michigan.

Elvis's '54 Caddy

Gasoline prices around $4 a gallon quickened defections from GM trucks, pushing the Detroit-based automaker to $69.8 billion in losses since 2004 and eroding its market share to 21.2 percent, the worst since 1925.

GM's shares last month fell to the lowest value since 1954, when Cadillac's popularity was at a peak. Back then, gasoline was selling for about a quarter a gallon, and Elvis was driving a pink and white '54 model.

Cadillac will add more versions of its mid-size CTS sedan and sport-utility vehicles that are smaller and more fuel efficient than the Escalade SUV, said the people familiar with the situation. They asked not to be named because the plans are private. The future of the big sedans will be decided later, when consumer demand for larger models is clearer, they said.

4,000 Pounds of Luxury

Wagoner said July 15 that GM will build a coupe version of the CTS, and today the automaker is scheduled to offer test drives to reporters in Detroit of a version of the Escalade that uses a hybrid-electric system to improve fuel economy.

GM spokeswoman Joanne Krell said she had no comment on future product plans.

The 4,000-pound DTS, loaded with leather, wood and a premium sound system, ranges in price from $35,000 to $55,000, according to Edmunds.com, which gathers vehicle data for consumers. The car gets about 15 miles per gallon in the city and 23 mpg on the highway, compared with the U.S.-required average of 27.5 mpg, which is rising to 35 by 2020.

The company that became GM's Cadillac division was organized in 1902 from Henry Ford's failed Henry Ford Co. Ford himself left to found Ford Motor Co. The brand took its name from the French explorer Antoine de la Mothe Cadillac, who established Detroit in 1701.

DeVille, Fleetwood

Over the years, Cadillac sold big sedans with the industry's first self-starters in 1912, first high-volume V-8 engines in 1914 and first 16-cylinder engines in 1930, Wolkonowicz said. In the mid 1950s, Cadillac outsold all other luxury makes in the U.S. combined, he said. Nameplates such as DeVille, Brougham, and Fleetwood dominated the brand.

``That was the heyday, when everyone dreamed of owning one,'' Wolkonowicz said.

Cadillac became an expression meaning the best of any class of goods, such as ``Cadillac of watches,'' referring to Rolex. The car inspired hundreds of songs, from Bruce Springsteen's ``Pink Cadillac'' to MC Nas'D & D.J. Freaky Fred's ``It's My Cadillac,'' and has starred in movies including ``Driving Miss Daisy'' and ``The Godfather.''

Cadillac sales started at three cars in 1902 and peaked at 350,813 in 1978, according to trade magazine Automotive News.

Lincoln, Mercedes, Lexus

Cadillac lost its six-decade claim as best-selling U.S. luxury brand in 1998 to Ford's Lincoln, which surrendered the lead to Daimler AG's Mercedes-Benz a year later. Since then, Toyota Motor Corp.'s Lexus has held the title.

Tustin, California-based AutoPacific Inc. expects GM to add the CTS coupe, a station wagon and at least two SUVs smaller than the Escalade in the next year or more, said Stephanie Brinley, an analyst in the auto forecasting company's Southfield, Michigan, office. Eventually, the DTS and STS may return as a single model, she said.

``They're making some tough financial choices right now and people may have to readjust their expectations of luxury a little smaller,'' Brinley said. ``But ultimately, large luxury sedans are going to have to be part of the large luxury brand.''

To contact the reporter on this story: Jeff Green in Southfield, Michigan at jgreen16@bloomberg.net

Last Updated: August 8, 2008 00:01 EDT