It doesn't look all that rich to me. 12:1 a/f isn't all that bad. I think I recall most people saying between 12.5 and 13.5 to be ideal. I believe most people shoot for 12.7 or so.
To me it looks like the car runs out of steam at about 5700rpm, when it should still be climbing in power. Maybe the a/f needs to be changed some up on the to end to make some more of that power. The rest of the graph looks incredible though! TORQUE
