I know there are millions of Fords out there with high-mileage 4.6L engines, still going strong. I used to have a '99 F-150 with that engine but traded it before 90K miles. I am looking at a 1-owner '06 F-150 that looks great, but with 211K miles; the majority were highway commutes and regular maintenance was done. Just curious about the engine's durability, in particular, SOHC timing chains and any other areas.

 

Welcome to the site!
Suggest you may have better responses posting in the 97-03, or the 04-08 sections. Here in 87-96 land, we're the 4.9L I6, and 5.0L and 5.8L V8 vintages. :-)
Offhand, ain't heard nothin' bad about the 4.6L but no idea on lifespans. Was advised to be leery of the 5.4L, especially the 04-06 years, due to spark plug spitting out...

 

I've seen several with head gasket issues. But overall they aren't bad.
There are also a few other problems for 4.6 V8 engine here https://cararac.com/blog/ford-4-6-v8...-problems.html