Well the '04 Ranger's 4.0l specs are this:
Base Number of Cylinders: 6
Base Engine Size: 4 liters
Base Engine Type: V6
Horsepower: 207 hp
Max Horsepower: 5250 rpm
Torque: 238 ft-lbs.
Max Torque: 3000 rpm
Remember, the '03 F-150 had the 4.6l like the GT, but had these numbers....
Base Number of Cylinders: 8
Base Engine Size: 4.6 liters
Base Engine Type: V8
Horsepower: 231 hp
Max Horsepower: 4750 rpm
Torque: 293 ft-lbs.
Max Torque: 3500 rpm
So, the 4.0l '05 Mustang may actually have around 225+ hp in it.
It seems they can get more out of the engine in a car.