You can also check the oil dipstick for oil/coolant intermix. It will look like a mayonnaise that has turned. You can also look on the underside of the oil filler cap for evidence of intermix. Why do you think the head gasket has blown? Is the car overheating? Are you seeing white smoke from the exhaust? Head gasket problems were not uncommon with the 3.8L
Start with take all the spark plugs out,keep them lined up to go back in the same cylinder,disable the ignition system pull the main electrical connector to the distributer or coil,DIS what ever then screw the compression tester in each cylinder,dont forget to push the gas pedal full throttle,then record your Cylinder PSI a head gasket problem will show two low cylinders next to each other usualy.