It should actually have 600-725 for the newer models and for the late models they should have around 550-600 that is they haven't added anything to the engine to make it improve it...
The 2010 model has 540 horsepower
The 1967 Shelby GT500 had 355 horsepower 428 big-block
The 2007 Ford Shelby GT500 has 500HP
it has a 5.8 v8 engine with 646 horsepower
From a low of 120hp to a high of 500hp in the 2007 Shelby GT500
The 2010 Ford Shelby-GT500's engine produces 510 ft-lbs. @ 4500 rpm.
The 2010 Ford Shelby GT 500 has ( 540 horsepower )
Shelby GT500 2007-09 models get 14/20mpg 2010 models get 14/22mpg 2011 models get 15/23mpg
There are two models available in the Shelby Gt500. Shelby GT500 - 500 HP / 480 torque Shelby GT500 KR - 540 HP / 510 torque
The 4.0L V6 engine only produces 212 horsepower. The GT high-performance 4.6L V8 engine produces 315 horsepower. If you go to the top-of-the-line Shelby GT500, superchargered 5.4L V8 540hp/510ft-lbs.
The 2011 Ford Shelby-GT500's engine produces 510 ft-lbs. @ 4250 rpm.
The 2008 Ford Shelby-GT500's engine produces 480 ft-lbs. @ 4500 rpm.