I have not shifted it at the RPM you suggest...If you have the graph for the dyno run, make sure you're shifting at the right rpm. When it changes gears you should be a few hundred rpm below your peak torque. Fixing that 60' time will definitely help too. Should be 1.6 or better.
peak torque is 527 lb/ft @ 4600 RPM. I have been shifting way too high then. peak HP is 523 @ 5800
I have tried at 5500, 6000, and 6500.