What’s the best year 5.0 to swap out the 4.0ohv
 

1996/1997 Ford Explorer 5.0l 4x4, buy the whole vehicle you will need a lot of its parts
1998 and up have PATS in the computer which is doable just another thing to deal with.

Since he already has PATS, wouldn't it be easier to just keep it with a '98+ truck that matches his returnless fuel system?

I used a '99 Explorer donor for my '99 Ranger and had no problems. The only thing I had to do was bring over the Explorer's PATS module (small box that's mounted behind the passenger airbag) and program in the original Ranger keys using Forscan when it was all done.

Okay I’ma just go with the 98+ that doesn’t seem to hard to do. another question for you what did you have to get like prays to put in and etc? Also how much did the total swap cost you?

Prays to put in?

$400 for a donor Explorer (2wd)
$150 for a 4wd 4R70W from a different Explorer
$200 driveshaft cut and balance
$100 4406 transfer case with linkage
$100 (ish, I don't remember exactly) to replace the fuel pump from my FFV 3.0 with a non FFV pump (wrong PSI)
$335 for exhaust work

Several thousand more in machine work and parts to rebuild the engine, replacing A/C components (compressor was locked up on the donor), etc. The small things definitely add up, but you can save most of that with a better donor vehicle.