When the 2015 Dodge Challenger SRT Hellcat hit showrooms this fall, it will boast 707 horsepower.

When it announced plans for the new 2015 Dodge Challenger SRT Hellcat a few months ago, Chrysler’s performance brand suggested it would deliver “600-plus” horsepower. It turns out that was a big plus sign, Dodge now revealing that what it is calling “the most powerful muscle car ever” will come in at a screeching 707 hp when it hits showrooms late this year.

All the numbers have taken a big jump. SRT Powertrain Director Chris Cowland originally suggested we’d be looking at torque in the range of 575 pound-feet. It turns out that will actually be 650 lb-ft.

But we anticipate that we can still take Cowland at his word, the engineering chief earlier suggesting that the 2015 Hellcat will be “bloody fast.”

All that power will be directed to the back wheels through a new eight-speed automatic gearbox. Fans of manual transmissions will have to settle for the less powerful 2015 Dodge Challenger R/T or Hemi Challenger Scat Pack models.

The introduction of the Challenger SRT Hellcat marks the first use of V-8 supercharger technology for Dodge and SRT, the muscle coupe drawing all that power out of the new 6.2-liter Hemi Hellcat engine.

The Dodge brand is clearly putting more emphasis on performance with the new Hellcat.

Among the more interesting features of the new model, buyers will get two different key fobs. The red one will, notes a Dodge news release, “unlock the full 707 horsepower and torque potential of the Challenger SRT Hellcat engine; while the black key fob limits the driver to a reduced engine output of 500 horsepower.”

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A full 91% of the engine’s content has been revised, according to Cowland, including new pistons, conrods, and crankshaft. More precisely, the pistons are forged, high-strength alloy, and the piston pins use diamond-like carbon coating.

But the critical piece is the screw-type blower from IHI. Asked why Dodge engineers opted for a supercharger instead of a turbocharger, Cowland explained this approach is, “a better match to the whole vehicle characteristics we were targeting, specifically instant throttle response and low-speed torque” than what a turbo could yield.

2015 Dodge Challenger SRT Hellcat has an active exhaust, the first fully active system ever used on a Chrysler product.

One of the more interesting features added to the 2015 Dodge Challenger SRT Hellcat is the active exhaust, the first fully active system ever used on a Chrysler product.

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The Hellcat also gets a new, selectable Driver Mode system, explained Russ Ruedisuelli, head of SRT and Motorsports engineering, which “allows a choice of shock settings, steering assist levels, horsepower, traction setting, auto transmission calibration and shift points. There are over 125 different settings.”

The new figures reveal that the Dodge Challenger SRT Hellcat will blow right by the new Corvette Z06, which is rated at a mere 650 hp. But both vehicles make 650 lb-ft of torque. The race is likely to be closer than that might first appear, as the ‘Vette will be significantly lighter than the Dodge.

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Meanwhile, that other mean machine from Dodge, the Viper, puts out just 640 hp and 600 lb-ft. Might the snake get its own version of the new Hellcat engine? Apparently not as, “It would require a ton of engineering,” Dan Reid, SRT’s director of product design and motorsports, told Autoblog.

Production of the 2015 Dodge Challenger SRT Hellcat begins during the third quarter, which should see the first of these beasts reach showrooms before it gets too cold to burn rubber on Detroit’s Woodward Avenue and other northern climes. Pricing will follow in the coming weeks, Dodge said.