I'm in the process of replacing the head gasket on my 77' 280.  I've disconnected everything touching the head, pulled the exhaust an intake manifolds, got the wood shim on the timing chain placed, cam sprocket if off, removed the 14 head bolts in the proper order along with the two front 10mm bolts. The head won't budge.   I've tried putting a breaker bar in the intake and no luck.  I'm trying not to go neanderthal.  Is there something I'm missing?  Let me add that there is evidence of pri