These are known as wet liner engines, as the cylinder sleeves, or liners, have coolant circulating around them. It is therefore critical that the figure 8 gaskets make a tight seal, as they prevent the coolant from leaking down into the oil. The sleeves protrude about 0.005" above the deck of the block, so that the cylinder head compresses not only the head gasket, but the figure 8 gaskets as well. If you are removing the head it is prudent therefore not to rotate the crankshaft while it is off; the pistons moving up can lift the sleeve (or so they say - in my experience the sleeves are so tightly bound in position with fifty-year-old coolant sediment that they need to be pounded out.)
