Any small bit of overheating will kill the head gaskets, get it over about 250 and the heads will crack, not maybe, they will crack. Water pump or radiatr goes out and you don't catch it imedietly and you will be doing head gaskets, its about a 14 hour labor time plus parts and machining (heads will probably need re-surfaced) and again most shops will tell you to get a new engine.
I agree that they do no like to overheat, but not all them will crack a head. I have an 02 4.7 ram, and I overheated it to the point that it wouldn't run anymore or restart after I shut it down (plugged rad playing in mud and didn't get it cleaned out good enough). I let it cool down, cleaned the rad and have been problem free ever since, and that was well over 60k miles ago (currently has right around 160k miles). I have replaced the timing chain tensioners once, but only because I put in HO cams so I did everything at the same time. My little 4.7 has been a good little engine, and I certainly wouldn't hesitate to buy one. I have numerous LA's, Magnums, and Hemi's and the 4.7 has been as reliable as any of them.
