The latest batches of Challengers see significant horsepower bumps in ALL fields, from the new Pentastart V6 making 305hp, the R/T making 379hp to the new 6.4L HEMI making 475hp.

Today’s newest generation retro-inspired muscle cars are just getting better with each passing month. We recently saw Ford’s resurrected BOSS 302 making 460 horsepower. Then there’s all the rumors swirling around the clandestine ’11 Z/28 rumored to share the CTS-V Cadillac’s 560hp LSA. All of this leaves the current Challenger back in a distant third…right? The muscle car that truly brought retro-styled muscle cars back in vogue, the Dodge Challenger, has not received any major updates since 2008.

Thankfully, that’s all about to change. These leaked documents from last week’s Dodge dealer event show that the 2011 Challenger is getting some much-needed updates including an entry-level 305-horsepower Pentastar V6, a 379hp R/T and the much-anticipated 475-horsepower 6.4-liter 392 HEMI. You’ll notice that Dodge is not holding back, intentionally including samples of competitor muscle cars that each tiered Challenger is aiming at. (See below)

The Dodge Challenger, while remaining aesthetically similar (though with minor tweaks like a revised front fascia and new horizontal tail light), will get a bevy of new engines and options. The base Challenger will now get the newly designed, and company standard Pentastar 3.6-liter V6 engine, which is good for a healthy 305 horsepower and 268 ft-lbs of torque, as well as getting upwards of 26 mpg on the highway. Not quite as good as the mpg from Ford’s V6, but not too shabby either.

The big news is that the SRT8 Challenger will get a significant horsepower bump, from 426-horsepower to 475-horsepower thanks to the bigger 6.4-liter 392ci HEMI. Yeah, they brought back the 392, guys. Retro no longer applies to the exterior. The extra 50 ponies is joined by another 40 ft-lbs of torque, bringing torque to 460 ft-lbs. The R/T’s 5.7-liter (348ci) HEMI also gets a pretty decent bump,  now with 379-horsepower and 410 ft-lbs of torque.

Of course, the new SRT8 will come with 20-inch SRT Design wheels, 245/45ZR20 tires, revised badging and stripes, Brembo brakes, premium suspension and steering upgrades, 180-mph speedometer, leather interior and the SRT TRack Experience.

Joining these new engines are several new Challenger special editions, including a limited run of “392 Edition” Challengers. These cars will come in either white with blue stripes or blue with white stripes, as well as a matching leather interior. They get a serialized plaque, dual full body stripes, forged SRT aluminum wheels, and “392” badges. Just 1,100 of these special Challengers will be built, celebrating the return of the 392 engine.

Dodge brand CEO Ralph Giles claimed the new Challenger SRT8 will get from 0-60 in under 4-seconds. Possible for such a hefty car? Perhaps. The Cadillac CTS-V weighs almost 100 pounds more than the Challenger, and does 0-60 mph in 3.9 seconds. Of course, it also has supercharged plant producing 556-horsepower. It will be interesting to see how this new crop of Challengers shape up to the rest of the muscle car field.