When we install a set of Aluminum Pontiac cylinder heads we use the following torque sequence pictured below.


Pontiac Head Bolt Torque Sequence


When we are tightening the heads up we typically do so using 30 wt oil for lubrication.  We also torque most of our aluminum heads up to 95 total foot lbs.  We do this in four steps.  The first step is to snug all of the fasteners up in the recommended sequence pictured above.  Step two is to tighten each fastener to 30 ft lbs using the recommended sequence.  In the third step, we go to 60 ft lbs. and tighten in the recommended sequence.  In the fourth step we go through the sequence one more time at 95 ft lbs.  We feel that this installation method gives us a very even tightening sequence and a very good head gasket seal.