Ford's Triton Engines have had some spark plug issues you may want to read about before you purchase this Van.
Why Do Spark Plugs Eject From Ford's Engines?
http://www.fordproblems.com/trends/triton-engine/spark-plug-ejection.shtml
Way back in my high school years when I was learning to work on cars, I was taught never to
install a plug with a longer "reach" than what was specified. (or one with a shorter one for that matter)
But Ford has been doing this with miserable results. What happens is that the exposed threads that extend into the combustion chamber become clogged with baked on deposits which makes them nearly impossible to
remove. This is where you hear about plugs breaking when they try to remove them. Also you hear owners
grumbling about how the plugs have very few threads in the cylinder head to hold the plug in place and when those under engineered threads fatigue the plugs are blown through the hood of the vehicle.
As a teen I would visit the local Drag Strip and watch the "AA class Blown Gassers" run. Often blowing their plugs when launching off the starting line. These were massive 392 Chrysler HEMI's that made as much noise
as you would expect if you stood next to the Space Shuttle on take off. (cranking out 1200 to 1400 hp)
But those were racing motors that ran a quarter mile in the blink of an eye.
These Triton's are service motors which should be dependable and last for years. (and haven't too well)
If I were going to turn some wrenches on these Triton's, I'd put a water injector on the engine and run it for
a month to decarbonize the combustion chamber. Then......maybe the plugs could be removed without much trouble. I would probably try to back the plug out a turn, if it would, and then hit the base of the plug
with a shot of PB Glaster or brake fluid and then tighten it up a turn. Then see if the penetration would allow
for removing the plug. (this may require three or four efforts over a weeks time)
Then I'd look to see if there wasn't a better plug with appropriate reach for this application, so this wouldn't be an ongoing problem.
But this is the most basic problem I've heard of with these Triton engines. I've seen these V10's in Vans. I can imagine nursing 10 plugs out of one of these V 10 Triton's and getting them all out without breaking one.