ls/vtec problem need to be solve, help!!

I got a ls/vtec setup with the following: gsr head on a ls block with gsr water pump, gsr oil pump, gsr timing belt, skunk 2 intake manifold, new rings and bearings, arp rod bolts and now a problem. When I first go it in my civic, it drove good the first week and after that some noise like "clink, clink, clink, clink, clink, clink!" came from the head sounding like a bold fell in there or something. It's not the valve b/c they have been adjusted perfectly. The motor runs normal at idle with the noise on once in a while. The noise would come on very bad at 2000 rpm and it would kinda shake too but pass that rpm it won't do it no more. I looked inside the head and no bolts in there are lying around and where the cams sits at it was kind of grinded up. So I put a new head on there b/c I though it was the problem but naw uh, it's still doing the same shit. The new head (a GSR head also) is very clean w/ no damage. That noise is still doing it very bad at 2000 rpm. It still sounds like a bolt felt in there. No leak from the oil line or the head gasket. Everything is good; it's just that noise. I don't know what to do now. Its not the head or the block since I redone everything twice so what can the problem be? Any idea?