Ideas on what's causing my click/tick/rattle noise?

my68barracuda said
What kind of valve stem seals are in the motor, umbrella or positive?
I agree that oil on the sparkplug threads is an indicator of a lot of oil getting into the cylinder. Are you seeing blue smoke out the tail pipe?

The seals are umbrella. I didn't see blue smoke like you would from an old clunker. However I did have visible vapor often.