The spark plugs are down in a recess in the center of the cylinder head. They are easily changed. Twist the spark plug wires on at a time and pull them upward. Inspect that oil has not filled the spark plug tube well (if it has it is a sign that the spark plug tube seals have failed and need to be replaced along with the valve cover gasket a common repair takes about 20 minutes). The spark plugs are removed using a 5/8 plug socket. The plug wires are retained in the distributor cap with black plastic clip that is removed to pull the spark plug wire out of the cap. Replace the wires one at a time to avoid confusion.