It's The next step up in Fords line of Modular engines. The 4.6 is the most prevalent engine at the moment, but Ford is pushing the bigger engine to become the "standard".
It is capable of that rated HP with some help.
Fords plans to go with the modular engine setup looked really good on paper, but, isn't working out to well in the real world. For example, the 4.6 has two block versions, the romeo and the windsor. Different castings in different factories, not to mention there are at least 12 versions of 4.6 heads out there, and not all of them are simple bolt-on swaps. So much for the modular idea, right?
Pound for pound though, I'd rather have the 02 Explorer engine. Even though it's the 4.6, it IS the same 6 bolt aluminum engine that comes in the cobra, just the cams are set to de-tune it. Very nice building block for a late model engine.