The Ford Mustang logo is displayed behind people gathering for...

The Ford Mustang logo is displayed behind people gathering for the unveiling of the new Ford Edge concept vehicle at the Los Angeles Auto Show. (Nov. 20, 2013) Credit: AP

Almost 50 years after Ford Motor Co.’s first Mustang introduced Americans to the fast and affordable pony car, the automaker is counting on a new design it unveils on four continents Dec. 5 to spur global sales.

Ford has kept a tight lid on its newest model, stoking speculation over how the automaker plans to handle a crucial tradeoff: honoring the look that has made the Mustang a classic, while also updating the car to compete with General Motors Co.’s more futuristic Chevrolet Camaro.

Getting the balance right has big implications for Ford’s rivalry with Chevrolet. The fifth complete Mustang redesign in five decades will arrive days after the Dearborn, Mich.-based company said the car’s U.S. sales dropped 7.7 percent in the year’s first 11 months and lagged further behind the Camaro.

The Mustang has long been a “halo car” that has helped Ford woo buyers to its broader lineup. The version that is being retired, a blunt-nosed and slab-sided design introduced in 2004 that evoked the models of the 1960s, juiced interest in the carmaker for almost a decade. It also presaged a Detroit design revival reminiscent of the postwar halcyon days when tail fins ruled the road.

More recently, the model has lost ground within Ford’s own lineup, with the Fiesta small car making a run at knocking it from among the automaker’s three best-selling passenger cars. Ford’s U.S. light-vehicle sales rose 7.1 percent in November to 189,705, more than a third of which were F-Series pickups. GM and Chrysler Group LLC led sales gains for the month with strong pickup sales to go with the best car lineup in a generation. Ford Fusion family sedan sales rose 51 percent.

Expanding Strength

“You can think about Ford as the Mustang and F-150 company,” said Eddie Alterman, editor in chief of Car and Driver. “Increasingly, that’s expanded to include Fusion and Focus. They’re becoming more and more known for these really well-designed, high-dynamic integrity sedans that are engineered in Europe.”

The 71,459 Mustang deliveries so far this year puts the muscle car further behind the Camaro -- with 75,552 sold over the same period -- for the U.S. sports-car crown.

“It would be great if we get that title, but we’re not going to do whatever it takes to get there,” Erich Merkle, Ford’s sales analyst, said yesterday on a conference call with analysts and reporters. “We’re going to launch the car and we’re going to let it speak for itself.”

Beau Boeckmann, who sits on Ford’s dealer product-advisory committee that saw the Mustang through its development process, said the company will honor the car’s history without giving short shrift to performance or avoiding visual changes that push its styling forward.

Retro Enough

Ford, the second-largest U.S. automaker behind Detroit-based GM, had to maintain just-retro-enough looks to pacify purists of the original American muscle car, Boeckmann said. Chevy’s Camaro, which hasn’t looked back since a redesign powered it past Mustang in the U.S. three years ago, pushed designers in the other direction. Add to those pressures the challenge of crafting the first Mustang that Ford planned to sell globally.

“The designers did an absolutely masterful job of bringing these almost juxtaposed positions together and making them work,” said Boeckmann, vice president of Galpin Motors, a Los Angeles-area dealership that is Ford’s top seller in the U.S.

Movie Magic

Ford pioneered pony cars with the introduction of the Mustang in April 1964, and it appeared in Switzerland in that year’s James Bond movie “Goldfinger.” Four years later in “Bullitt,” Steve McQueen’s good guy drove a roaring, squealing Mustang in an extended scene that helped redefine the movie car-chase. Mustangs were characters in their own right in both 1974 and 2000 releases of “Gone in Sixty Seconds.”

Redesigning a car as crucial as Mustang is a fraught process akin to when GM updates its Chevrolet Corvette or Bayerische Motoren Werke AG reimagines its BMW 3 Series.

“At some point, you have to get revolutionary,” said Kevin Tynan, an auto analyst for Bloomberg Industries. “At some point, you have to let go because new buyers don’t really care about the retro cachet of the Mustang. I would like to think that this would be the last evolutionary redesign of the Mustang before we get something completely new.”

The Mustang scored its best sales figures in the 1960s, when Ford built more than 600,000 in a year. Ford was knocked for its second-generation model, which added weight from new safety and emissions equipment even as its dimensions shrank and its performance was diluted by weaker engines. The fifth generation that exits next year, developed under Hau Thai-Tang, who now heads purchasing at Ford, was largely credited with recapturing the Mustang’s mojo.

Classic Cues

Car and Driver splashed the cover of its December issue with a picture of what it said was “almost definitely” the latest Mustang, and its website allows readers to scroll through a 360-degree view. The rendering retains Mustang’s low, nose-down profile in the front end and its trademark three-bar taillights in the rear.

The magazine predicts that Mustang’s exterior dimensions will shrink and that it will shed a styling that stands alone within Ford’s lineup, and instead share a number of design language cues that have been led by the Fusion sedan, including an “Aston Martin-via-Dearborn mouth” as its front grille.

“Ford is just kind of evolving this car and not taking a huge swing toward a completely different concept,” Alterman said. Cars such as Porsche’s 911, Chrysler’s Jeep Wrangler and even the Corvette share “this slow, methodical evolution to bring the cars into the modern era but still retain their essence.”

Global Unveilings

Ford has attempted to stoke excitement for the Dec. 5 debut -- which it will host in Barcelona, Shanghai and Sydney, as well as New York, Los Angeles and Dearborn -- with a 15-day countdown on Facebook and Instagram that called on users to share their Mustang stories.

Car and Driver’s Alterman said his first car was supposed to be a 1985 Mustang LX Notchback, with one of the car’s infamously powerful 5.0-liter, eight-cylinder engines. The owner of the Mustang, his father’s co-worker, crashed it a few months before Alterman earned his driver’s license and could take over the keys.

“I never got a chance to crash it myself,” Alterman said by telephone. “It would have been a potentially lethal error on my parents’ part to allow that to be my first car.”

Mustang Memories

Keeping the Mustang true to its roots evokes memories of the first three new cars driven by Boeckmann, whose father Bert Boeckmann pioneered auto customization in the mid-sixties and seventies.

Beau Boeckmann, 43, said his first Mustang was a blue 5.0 that he drove to school and to an Oingo Boingo rock concert. He said he met lead singer Danny Elfman backstage and gave him a parking-lot test drive of the car after the show.

“Almost everybody’s got a Mustang story, or something they did in a Mustang maybe they shouldn’t have done,” he said.

Of course, Ford’s ultimate goal will be more than just good vibes for a model that was the top-selling U.S. sports car for 24 years before losing the spot to the Camaro in 2010.

In a first, the latest Mustang will be sold in Europe despite having remained very much an American project. Ford executives have shrugged at the thought of any risks that the car will be a tough sell in markets where it’s never competed.

“Every time we talk about Mustang, there’s always been a demand and a want from some of the other markets that see the vehicle and see what it stands for,” Raj Nair, Ford’s product development chief, told reporters in April. “It’s an American icon, but it’s not just a solely American passion.”

International Audience

Car and Driver predicts that Ford will offer the first turbo­charged four-cylinder engine for Mustang since the 1986 SVO model, and introduce an independent rear suspension to improve handling and ride. The four-cylinder engine may make Mustang an easier sell in Europe, where gasoline prices can top $10 a gallon.

Still, Mustang is likely to play little more than a bit role in Ford’s push toward 8 million annual vehicle sales by mid-decade, Alterman said. He expects Mustang to be a “niche” player more of a “design statement” or “style car” than the sort of utilitarian models that sell well in Europe, such as the Focus compact.

“Even though it’s been trimmed up, it’s still a pretty American proposition,” Alterman said. “That’s smart. It’s boldly American and it should be. It shouldn’t be a watered-down Euro coupe.”