The ticking sound is your engine oil dropping down into the pan after the engine is shut off. That makes a ticking sound because the pan is a lot cooler in temperature then the rest of the engine and the engine oil. So as it drops on the pan it makes noise. It is normal (keeping in mind the fact that the engine has been TURNED OFF).
What Causes A "Ticking" Or "Dripping" Sound From The Engine Or Under The Hood When The Engine Is Shut Off?
Not the engine block. It is probably the exhaust headers cooling off, or the exhaust header sheilds if it has them.
Heat and the contraction of the engine block