For the AFR to get rich towards redline is normal, in any engine, I believe it is using the fuel as cooling at those high loads.Hasn't anybody noticed how ALL of these AFR maps shows the ratio getting ridiculously rich from 9000 to 9500? That's the way to lose HP where you could use in ( on a track anyway). Are non of these PCV's or reflashed. I just checked my post reflash post induction restriction removal AFR graph and it's the same. There is more useable HP lurking in those engines unless there is a port , airflow restriction, camming problem, air resonance, valve spring, problem waiting to be fixed. Something is still stopping the air getting i at high revs.