Originally Posted by
mlin32
Do-able especially as you have priority for passport contrôle. No bus to take (FCO will be from 2F), and there's even the possibility you don't need to go thru security again arriving from the USA.
Plenty of flights daily you will be automatically rebooked on if something goes wrong.
DL metal tends not to arrive at the proper L gates for doing an airside non-Schengen to Schengen connection... DL pretty exclusively arrives at K or M.