Clicking head noise

I just replace my cracked header on my 95 4.0HO AW4. I can actually hear my engine now! Now that things are quiet I hear a clicking noise coming from the valve cover. Are these the rockers moving up and down? What is making this noise? Is it something I need to fix? I do not know much about the internal workings of the engine so help would be appreciated.
Thanks
Ben

XJ's are known for noisy lifters. You can try an additive such as EOS or similar, sometimes that helps. I had to replace the lifters on my '90, its a big job but worth it in the end!

Depending on the age of your injectors they can also make a "click" when the spring snaps back inside them after firing.