Hello everyone. It's been awhile since I've signed on, and to be honest it's been awhile since I've touched my old Z. I was running the car all last summer, and it ran great. It had great power, and pulled really strong. I'm running ZTherapy rebuilt SU's which I synced and tuned, pertronix ignitor, and just an MSA 6 to 1 header. I rebuilt the engine but had the head sent out to Mancini machine, where I know they re surfaced it, and I can only assume they checked, repaired, and assembled the head correctly, as this was some years ago. I was driving the car one day and I thought the valve train sounded louder than normal so I preceeded to pop the cover off and check my valve clearances. I found that a few lobes on my cam are black, not shiny like the others. I also noticed that the oil is dark for how new it is. I'm wondering if I ran the valve clearances too tight on these valves and damaged the surface hardening of the cam. I ran Lucas oil stabilizer in this engine when I was driving the car as well. Also used some ethanol fuel treatment in the gastank. Any feed back would be greatly appreciated.