one word of caution, don't be alarmed. when you replace the plugs, vacuum out the well they set in before removing the plug, and prior to inserting a new plug, AND use a torque wrench to tighten them to spec's.
why? they are aluminum heads, and there aren't many threads that hold the plug. if you don't get all the dirt out ( its a deep well the plugs sit in because of the head height ), or, if you don't tighten correctly, the plug will work its way loose, and when it gets near the top of the threads, the compression will spit it out, stripping the last couple of aluminum head threads. this is not un-common on 4.6L and tritons. its not rocket science, just keep the well clear of dirt, and tighten to spec's, using a torque wrench. if memory serves ( check me on this, my memory doesn't serve as well as it used to
, its INCH pounds, 120-180, which can be converted to foot pounds.