Google "coyote mark viii" there is a twin turbo 5.0, looks narrower and shorter than a DOHC 4.6. The differences between the truck 5.0 and mustang are truck has lower compression, different cams, missing things like oil jet piston cooling, externally the intakes are different, and different tuning.
Not that it would be easy, but with the PCM and cluster from the donor isn't that bad. There are some MN-12s with the 5.0, some done better than others.
As the F-150 with the 5.0 is marginally slower than my 97 Mark VIII (but the Ecoboost is faster), with the lighter weight of the car would be a pretty good combo.