My freshly rebuilt engine has about 365 miles on it now and it has developed a slow coolant leak. After an hour of driving, it loses about 1 cup of coolant from the overflow reservoir. There is no coolant on the ground, but on the passenger side I found some coolant dripping from the outside center cylinder head bolt which made me think one of three things:
A) Leaking head gasket
B) Does the cylinder head bolt hole go into a water jacket?
C) Do either of the center exhaust manifold bolt holes go into a water jacket?

There is no coolant in the oil and no oil in the coolant. The exhaust is clear (no white vapor) and doesn't smell sweet, so I'm thinking that makes B or C more likely. Additionally, there is coolant not just dripping off the cylinder head bolt, but there are actually drops of coolant on top of the head of the bolt, so it must have dripped onto it from the header flange. Does anyone know if the 360 has either cylinder head bolt holes or exhaust manifold bolt holes that go into a water jacket?

 

I do believe that hold can get into the water jacket. Don't know if RTV, or Teflon tape would be adequate to the task there.... heat may do it in. Maybe pipe dope?

 

As I recall, I do not believe the exhaust manifold bolt holes extend into the water jackets on the magnum heads. I'd suspect you may have a crack in the head that's leaking the coolant.