5.4l 4r100 swap into a 4.6 4r70w?

[IMINYOURCHAIR]

stupid me forgot to keep checking the exposed engine I have in the green machine and it got uncovered slightly and now the exposed bores got water from condensation in them and are rusted pretty bad. I have a 98 expedition here that has frame and body rot but a usable engine and trans although it's a 5.4 4x4 how hard would it be to swap outside of the obvious wiring harness, gem and transmission differences? the 4.6 has a worn transmission at 303k miles anyhow. I need to get rid of one of these trucks since right now I can't drive either of them.

 

[Kwik SC]

Entire rear subframe is also different. The 4.6 has an 8.8 rear while the 5.4 has a much stronger 9.75 rear. Its time consuming but totally doable as my friend did the exact same thing to prep his 4.6 truck for a 5.4 with a lightning blower setup on his.

 

[IMINYOURCHAIR]

so the rear arms and whatnot won't swap? I don't know the condition of the rear end of the donor but I think the lsd is either welded or stuck. both tires spin and it binds in hard turns.