Doug,
I may be one of the two friends Jeff refers to above. Let me add the V-10 is NOT the only Ford Triton series engine with the spitting spark plug deficiency. All Triton engine have been affected including the 5.4L in trucks, the 4.6L in Mustangs, etc.
While Ford disclaims all responsibility for a poor design resulting in a manufacturer's defect (all MY opinion and you'll see why in a moment), even certain government agencies supported by taxpayer dollars seem to have sided with Ford regarding this issue.
In my case and after being quoted in excess of $3,000.00 to repair (head replacement still leaving five plugs on the other head that could blow out), I opted for a repair kit from Time-Sert (you can Google them) and repaired the blown threads myself. I do keep this kit in the truck in case another plug blows out. The repair is actually easy to perform but of course it is one hole at a time.
My truck is a 1999 F-350, Triton V-10, 5 speed manual, FWD and 4.33 differentials. I bought it with 60,000 miles on it and it now has 135,000 miles on the odometer. I've since replaced both rear springs once each, paid to replace a flywheel, clutch and transmission, and more. The flywheel, clutch, transmission incident was due to broken flywheel bolts.
Built Ford Tough? I think not. It is doubly hard for me to swallow Ford's propensity for NOT standing behind their products (I said above you'll find out why...) because I work for Ford! I am involved with manufacturing (stamping). Luckily I am NOT part of Ford's Power Train operations!
With all the above said, I still like the truck and it does perform as expected. However, I am constantly leery of "What is gonna break next and how much is that gonna cost me?!?!"
BTW, I don't think I mentioned it but Ford redesigned the spark plug holes in Triton heads approx late 2002 or early 2003. If you purchase something built after late 2003 or newer, you should be getting a vehicle with redesigned heads.
On a more pleasant note, I've recently picked up a new 2007 Focus ST and so far, I'm highly pleased with it. Not tow vehicle though obviously so I won't go on about it. <grin>
Tim