Hey bro
I had exactly the same problem with my GTiR. I bought a whole engine just for the head becasue I was sick of the noise and my car was known as the "tractor". Do it before you wreck something, the rocker arms on my head were stuffed because the shims were all mixed up, the little feet of the rockers that sit on the shims were all worn on an angle. So reshimming would have been a waste of time. If you do it now, your rockers might still be okay.