[Adger Smith]

Michael,
There are sooo... many varaibles in tuning with O2's. I really agree with the idea that there is no "one" number for every combination. Cam overlap is one of the biggest players in what goes out the ex pipe, even low compression vs high compression will make a slight difference in the best O2 number.When you change cam C/L or valve lash or timing on your own combination that you are familar with and have data.. the O2's can change, usually do. The new O2 reading may or may not be the place the engine is happy and making peak power. The old O2 point may not be the best power setting with the changes. You have to search the combination/tune up for what makes the engine happy. A happy engine will usually make you happy because it is making power.
Oh, Please Read the plugs when making changes.... (don't be lazy.. does a plug wrench still fit your hand?) I know, I know it is so easy to take a reading of the data and pound that key board to make changes,,,, but reading the plug is the way to tell what is really going on in the combustion chamber. :~)