Developed a tick

I am, but I have no idea what the previous owner used. I have been using 10w-30 Valvoline VR1 Racing "with high zinc". Can anyone suggest alternatives that might be better for the future?

Sounds like I will be pulling the intake tonight to get to the cam and lifters. What's the best way to confirm if the lifters are dished? Lay a straight edge across the bottom and look for a gap?
You are using very good oil. I have run it for years with no problems. You can use a straight edge, it real easy to tell not tricks to it.