The early tritons had the short threaded problem and there's LOTS of stories of blow plugs (hence the Heli coil comment), the later ones had two piece plugs that often broke when trying to remove.
And than as mentioned the manifold bolts, I replace mine on my last truck ('98 5.4). Talk about a pain in the a$$, but other than a few choice words and some of my time I saved about 400.00 bucks doing it myself.
