Originally Posted by 
p38arover
				
			 
			My boss at Moree Satellite Earth Station in 1968 had one.  It blew a head gasket so myself (I was still a trainee radio technician) and one of the Plant Officers were assigned the job of fixing it.  We unbolted the heads (flathead V8) but they wouldn't come off.  In the end, we started it up with the head bolts fitted but loose so that if the heads came free, they'd be restrained.  The blasted things still wouldn't come loose.  So we had to belt them with a small sledge hammer whilst running the engine.
I think the heads were alloy but I can't be sure.