the speed limit is what the auto can pull. most of the time it drops out of converter lock up and you can only manage 210 220 pushing it. they dont have what ford have on there early cars which is what feels like a cut out (rev limiter type thing)
desclamer:i dont condone speeding and if you are speeding than it should be done on a closed track or in controlled conditions
From what i hear a standard VS auto will max out at 215 in third, a few have said that overdrive wont crank over at WOT. It's not exactly a speed limiter, more a limitation of the car itself.
The older fords did have an electronic speed limiter on them, as an above poster said. They're limited to 170-180kmh?, as the diff/axle may suffer damage if the car goes any faster