Quote: Are you sure it's not exhaust related? How about the heat riser in the exhaust manifold rattling?
Also with that cam did you make sure that you have enough valve spring to go avoid coil bind and did you check the clearance with the valve open of the valve spring retainer to the valve guide and seal. You need at least .060 more travel in the valve spring than the actual valve lift and at least the same amount between the guide/seal and the spring retainer. You did check installed height and make sure of closed spring pressure at installed height. Loose springs can be noisy.
Also with that cam did you make sure that you have enough valve spring to go avoid coil bind and did you check the clearance with the valve open of the valve spring retainer to the valve guide and seal. You need at least .060 more travel in the valve spring than the actual valve lift and at least the same amount between the guide/seal and the spring retainer. You did check installed height and make sure of closed spring pressure at installed height. Loose springs can be noisy. 
