help setting up my 8 3/4!!!
How about this: Stick that sucker in selected second and take it for a romp.
Where does it make the most seat of the pants power in and around 3k? Stick your cruise rpm right there. That will balance power and economy.
I see it time and time again, you pick a gear that lugs the engine and when you rev it up a little you get better mileage. Cam and converter selection is a big part of it too.
Best fuel economy comes around bottom of the torque curve.
Screw the voodoo. Read this:
http://www.jalopyjournal.com/forum/showthread.php?t=773608