The redesigned 2015 Ford Mustang will be slightly smaller and several hundred pounds lighter when the car goes on sale next year, Edmunds has learned.

The Mustang will shed around 400 pounds in a quest to improve fuel economy, said a source familiar with the Mustang program.

The dimensions of the 2015 Mustang will be reduced and the car will use lighter-weight materials as well.

DEARBORN, Michigan — The redesigned 2015 Ford Mustang will be slightly smaller and several hundred pounds lighter when the car goes on sale next year, Edmunds has learned.

"I know they are trying to remove a minimum of 400 pounds," said a source familiar with the Mustang program who asked not to be identified. "The big thing is that it will be a 'smarter' size."

The 2014 Ford Mustang V6 coupe has a curb weight of 3,523 pounds when equipped with the six-speed automatic transmission and 3,501 pounds when equipped with the six-speed manual transmission, according to Ford. The 2014 Ford Mustang V6 convertible has a curb weight of 3,652 pounds when equipped with the six-speed automatic transmission and 3,630 pounds when equipped with the six-speed manual transmission.

The 2014 Ford Mustang coupe with a 3.7-liter V6 engine and six-speed automatic transmission returns 19 mpg in city driving and 31 mpg on the highway, according to the EPA.

Ford did not respond immediately to a query from Edmunds asking about the Mustang weight-loss program.

Automakers are required to boost the fuel economy of their fleet 4 percent annually through 2025.

"That car will be around for 8 to 10 years so it has to meet anticipated regulatory requirements for that long period of time," the source said.

One of the keys to boosting fuel economy is trimming vehicle weight, by reducing the dimensions of the new Mustang and using lighter-weight materials.

"There is going to be less overhang" in the front, rear and on the sides of the Mustang, the source said.

"The overall length will be something like 8 percent (approximately 15 inches) shorter," the source said.

The 2014 Mustang is 188.5 inches in length and rides on a 107.1-inch wheelbase.

"The width will be a little less than 10 percent (about 6.5 inches) narrower," the source said.

The 2014 model is 73.9 inches wide.

As for materials "they are going to use more aluminum, better structural engineering in terms of spot welds and so on and so forth, basically using less material and making it stronger," the source said.

However, there is "nothing terribly exotic" in terms of materials.

"It is still going to be a pony car. It is still going to submit a (reasonable) price point so it cannot be an exotic," the source said.

While pricing for lower-end Mustangs is expected to be comparable to today's models, the source said high-end models could see a dramatic increase. The base 2014 Ford Mustang starts at $22,995.

"My understanding is that the maximum price is going to go up about 10 percent and that will be depending on equipment," the source said.

The 2015 Mustang coupe is expected to be unveiled at the 2014 Detroit Auto Show in January or the 2014 New York Auto Show in April. The convertible will debut later at a separate show. It will not be unveiled with the fastback, the source said.

Edmunds says: The 2015 Ford Mustang may shrink in size, largely due to regulatory pressure.