Chrysler's muscular-looking 300 series sedan reportedly is about to get another dose of steroids.

The hot-selling car, which critics have hailed as marking a renaissance for the spacious American-styled sedan, already comes equipped with an optional 5.7 litre Hemi V8 engine with 340 horsepower, powerful enough to launch it from zero to 60 miles per hour in just 6.3 seconds, Reuters noted.

Beginning next spring, however, DaimlerChrysler's Chrysler division will offer an even faster version of the 300 with a 425-horsepower, 6.1 litre Hemi V8, the report added.

The 2005 model car, tuned to deliver greased-lightning takeoffs and a top-rated US speed of 170 mph., will be known as the Chrysler 300C SRT-8.

"We're talking zero to 60 in around five seconds," Dan Knott, who heads Chrysler's high-performance Street and Racing Technology (SRT) division, reportedly said of the upcoming hotrod.

"That's a pretty stout performance for a sedan of this size," Knott told Reuters. Styled mostly like other 300s, with their massive slabs of sheet metal and out-sized chrome-plated grille, the rear-wheel-drive vehicle will weigh in at about 4,100 pounds.

Big 20-inch forged aluminum wheels and a specially designed rear deck spoiler will be among the design cues setting the car apart from other 300s, Reuters said, adding that it will only be available in exterior colours dubbed "bright silver" and "brilliant black."

"We're tapping into the heritage of the Hemi and, in this case, we basically injected it with a good old case of SRT hormones, or steroids," Knott reportedly said.

He spoke to Reuters in a phone interview as Chrysler prepared to make a formal announcement, at the Pebble Beach motor show in California on Friday, about production of the 300C SRT-8.

Hemi is a name that harks back to Chrysler's muscle car days of the 1960s and '70s, and Chrysler chief executive Dieter Zetsche reportedly says it has more brand equity than he has ever seen before for an engine.

The popular, new-age version of the engine, built at a Chrysler plant in Mexico, is available in Dodge pickups and sport utility vehicles as well as the 300, and it has become an increasingly important part of Chrysler's overall sales, Reuters noted.

"Hemi is a household name," Anthony Pratt, senior manager for global powertrain at JD Power and Associates, told Reuters. "It's like the 'Intel inside' [personal computer processor] concept," he added, referring to Chrysler's marketing of the engine.

Knott reportedly declined to comment when asked what other vehicles might be offered with the all-new 425-horsepower Hemi.

But Pratt told Reuters automotive supplier sources have told him the engine would be put in at least some models of the all-new 2005 Dodge Charger sedan and possibly a high-performance version of the recently introduced Dodge Magnum sport wagon.

The engine is also likely to appear in a high-output version of Chrysler's all-new Jeep Grand Cherokee or some other Jeep derivative, Pratt told Reuters.

The fuel economy of the 6.1 litre version of the Hemi is far from great, and the 300C SRT-8 will only get about 14 miles per gallon in city driving and 19 on the highway. Because of that it will also be subject to the US 'gas guzzler' tax, the news agency noted.

Knott reportedly stressed that the large car, which should only burn premium fuel, was designed for the sort of people who don't typically worry about fuel economy, however.

"It's a collector-series vehicle, a performance enthusiasts' vehicle," Knott told Reuters.