It wasn’t too long ago that the Shelby GT500 was the only game in town, pumping out over 500 horsepower from its supercharged 5.4 liter engine. My how a few years can change so much. Now not only does the Shelby GT500 have to compete with the 470 horsepower 2011 Dodge Challenger SRT8, but also the 550 horsepower Chevrolet Camaro ZL1. But it would appear that the Blue Oval is one step ahead, as rumors circulate across the Internet that the next Shelby GT500 could pack as much as 620 horsepower.

Inside Line came across these spy pictures of what could be the 2013 Shelby Mustang GT500, and while the design doesn’t give away too many clues, it’s got our mind all-abuzz.

What has us so sure that this is the next GT500, and not just another Mustang mule? Well for one, there’s that distinctive Shelby spoiler (though that could be meant to throw us offer the trail.) It’s also got massive exhaust tips but appears to be missing the rear diffuser (is that a fuel cell we see under there?) It’s also wearing Shelby GT500 shoes inside those big tires, and there’s a plastic Shelby snake on the front grille, so we’re pretty sure what we see here is the next-gen GT500.

And what does Ford have planned, you ask? Rumor has it that the 5.4 liter V8 engine will be enlarged .4 liters to 5.8 liters, and power could be bumped up to as much as 620 ponies. Inside Line says that they managed to get a 12.5 out of the 540 horsepower Shelby, so with 620 ponies under the hood it should easily make the ¼ mile dash in the 11-second range.