I want to know what are all the holes for on a engine block deck surface? I Know some are to help with putting the cylinder head on and others are to bolt the head down. But what are the rest?
The other holes are to allow coolant and/or oil to flow through the cylinder head and engine block.
The coolant is needed to help cool down the combustion chamber.
Here is an example of a Chrysler engine block with coolant holes.
On overhead cam engines the camshafts require oil for lubricating the journal bearings that they spin on.