I'll go back and edit my post for more info. You should run power loops. Get a base line, then try shifting at different rpm till you get the lowest ET. Make 2 or 3 runs at each rpm to get a good read.
Yep, that's it^^^^^^. Pick a very safe rpm to shift at, get a consistent number, then increase rpm, and test. (Trying not to exceed BOOM rpm)
Best et shift point is often a couple hundred rpm above hp peak, but not always. Shifting at peak torque is a guaranteed way to slow way down.
I have found with my 440 that it et's as well at 5900 as it does at 6300, probably due to the 906 heads, even though it will easily turn 6500. So, I shift it at 5900. No reason to high rpm shift if not necessary.
