We thought the 6.1-liter Hemi in the Dodge Challenger SRT8 was enough to make anyone giddy, but apparently a 600-horsepower 8.4-liter V-10 was too much of a "what if" not to produce -- right up there with "what if we put a Hemi in a lawn mower?" If you happen to see a Tornado Red Dodge Challenger with a "Viper Powered" logo on a shaker hood, don't try to drag race it, just get out of your car and bow your head in awe.