[Rick Parker]

John:
If you are running solid lifter cam, be sure valve lash is correct. Even at that it will be noisier that a hydraulic lifter cam. At least you have eliminated the possibility of rubbing between the rockers and the covers.
Get a stethiscope or put a long screwdriver on the head, intake manifold and other various areas while engine is running with the other end to your ear. You can hear a lot this way. If you hear something abnormal check it out. They will never be as quiet as a current domestic V8.

Good luck
Rick