Imo, with a cam like that....... there is too much “back flow” going on at idle for me to trust the O2 sensors to be accurate.
I’d just tune the idle so it “runs right”, and the O2 readings just are what they are.
That’s what I’m doing, I checked plugs many times today and have nice burn marks on my hands from headers as reminder ;-) It was a good day!
I need to get used to the car now.
My previous cam was 259/[email protected], 108 lsa with .450 lobes. Somehow with the new one it feels like big jump with power. It didn’t idle great either ;-)