The taper points up towards the injector. It gets crushed down when the injector is installed.
What's the issue you're seeing with the head other than lots of soot in the injector wells? Can't tell from the photos, are the sealing surfaces pitted? You might be able to clean it up rather than pulling it apart.
Fastest/easiest way to get the shields out, btw, is to spin the engine on the starter motor, compression blows them out with no struggle even when they are stuck fast.
