Hi All. I'm driving a striking deep ruby red 2014 Mustang with a 305 HP 6 cylinder engine. Even with the automatic, it goes like spit. It has an excellent turbo charger, it seems. I came here wondering about my speed governor. The speedometer shows speeds up to 200 mph, but on a long empty straightaway recently, I could not get to 120 mph. In fact, it seemed to lose all power at 114 mph or thereabouts, yet it had picked up speed smoothly & powerfully right up until then. I must conclude a speed governor is installed. Not that it usually matters, but I was disappointed: I wanted to hit 120 mph since in my older cars that was the top speed listed on the speedometer.

 

Looks like Ford limits to that speed. Here is a thread on another site that talks somewhat about it.

http://www.mustangevolution.com/forum/f356/t316494/

 

Yes the Mustang has a speed governor built in from the factory.
The V6 models are limited to a lower speed than the V8 models, for at least a couple of reasons, one being the terribly weak driveshaft that Ford installs in the V6 cars, and another being the lower-performance tires usually installed.
So even if you do get a tuner and disable the governor, keep in mind that people have already done that to 2011+ V6 Mustangs and by 120 or so the driveshaft has come apart. Not a fun thing to experience at 120-130 mph.

Oh, and no, you car is not turbo charged, at least not from the factory.
The engine is a naturally-aspirated 3.7L V6.