Mark, 9,400 is some good RPM's providing that its not lean, the reason asked I was wondering just what that 120 AX was like as compaired to a YS 120 . The numbers are close as far as static goes for one of my older SF 120's.
Oh one more thing i'm sure you used a pits style muffler and if so did you have a fuel draw issue.
Thanks for the info Happy flying.