FuzzyMcFuzzums

Okay, I have a 1993 pickup, LC head/cam all that good stuff. Once I hit 3000 rpm, i have a hissing/metallic sound, not rod knock, I had my valve lash set to zero. I adjusted to factory spec, still there. Thought it might be rockers smacking the valve cover, went to 3/4 turn after hand tight.... still there. Timing is at 7 degress BTDC, Original injectors. Is this spark knock/detonation? It only happens at 3k or higher. A little over 6k on a rebuild, I just reset timing today; the noise was a little lower pitched at 3 degrees BTDC, i advanced it to hear the cam roll. But reset timing today. Could it be injectors? It sounds like a pissed off robot rattlesnake is in my truck... however, i do know that the clips on my throwout bearing are broke, it rattles around when clutch is engaged. Maybe that's it. Its odd, though, Ive dealt with rod knock before, I've heard piston slap, but never this. Hopefully something simple, I dont have any loss of power, or misfiring, no metal shavings in my oil, (just changed it yesterday). So I need your wisdom.

FuzzyMcFuzzums

Started truck last night after adjusting valves, grinding noise. So I'm going to look at the timing chain, probably the crappy rock auto tensioner. Still seeking advice, suggestions etc