Steve,
What about the shift points in other gears? With the throttle wide open, I can't get above 5K without an upshift. Is this where you would adjust the pressure cable to get the shift point higher?
Cheers,
Joe
PS. Here's that post on a 500E with similar symptoms. Discussion points are almost all the same.

http://www.peachparts.com/shopforum/showthread.php?threadid=5168&highlight=bowden+cable+front