Ford Triton V-10 Spark plugs

We use strictly ford trucks and econline vans at work. I've helped the mechanic repair the threads when a spark plug blows out. They have coil packs so they don't actually "blow out". At least none of them I've seen have. We have changed plugs a few times and had the plug tip break off, probably due to carbon buildup. I'm not sure though.

We've also had three different 5.4's with cam issues. The engine starts making noises that get worse over time. I'm not sure why but the cams go flat! One truck has 240k miles and is in great shape, trans is great, body, suspension, etc. But the cams have been replaced 3 times. Once under warranty. Second time the mechanic replaced them. Third time we had ford replace the cams, followers, rockers, etc. Its now ticking again and has too many miles to bother fixing it.