How easy would this swap be?
shouldn't be that bad at all. the biggest problem you'll have is ECU tuning for the extra displacement
timing trigger wheels on the camshafts for 03 and up 3 valve motors and power steering might be a hassle.
I done a 98 swap very straight forward for me. the easy part about 2 valve motors were the single cam trigger wheel
I had a wheel made from a CNC machine along with a crank trigger retained all of the wiring and sensors. the 6.2l and 5.0 do not use coolant in the intakes so you will have to shut off the ECT sensor in the ECU.
here's another alternative which will be less money to spend than a 6.2l engine unless you some how get it really cheap.
get a big bore 5.4l block 3.700 piston they go right on the existing rods port the heads whether its 2 valve or 3 valve they all need it, you'll have to change the bottom of the intake for the extra displacement it needs to hold more air 4.6-5.0 and 5.4l-5.8l bigger TB stock injectors are fine no need to waste money on injectors, headers, you can also get a decent cam grind from comp-cams to retain peak torque just little higher lift. this is about 370hp/410tq engine with ease. the small bore will always restrict torque and power production on any ford engine besides the 6.2.
the 6.2l and 5.0 uses the factory 4.6 and 5.4 trans bolt patterns so thats a plus for any one.
its not a hard swap.