Have a 2008 and looking to swap in a 351W 408 engine.
My questions are on the wiring using a ford harness.
Question: What would work the best using stock harness?
I am looking at one out of a 2000 5.0V8 Explorer I know it will work, how much can I use from the 08 harness? It has a v6 in it now?
Next question is on the intake I want to use a better stock one, the 302 in 2000 had the GT 40 upper & lower...with the GT 40 upper bolt on the 1991 351 lower EFI intake? With or with out modifications?
Suggestions helpful anyone does this swap ?

Thanks

 

You'll have to start from scratch on the wiring as nothing is compatible.
Just use the 2000 harness and ECU or better, see if you can get everything from a 91 out of a junk yard.
Your upper intake will bolt to the lower 302 intake without modifications.

For a 408 though, those intakes might be too restrictive. You'll have to do some research on that...