Cylinder 8 chirps when fired.

[regislovato]

my old head gaskets had a compressed thickness of .047 in, but my new ones are slightly flatter, at .043 in when compressed. My block and head surfaces were perfectly flat and clean before I put the gaskets on, and I torqued the head bolts down to 72 ft lbs as specified by my manual, in sequence, in three steps per bolt. My Spark Plugs are brand new, and look fine. I heard somewhere that I should re torque the head bolts after letting the engine cool down after running it until it reaches its normal operating temperature, but others that I have talked to say that's unnecessary.