The Trans-Go TF-2 kit will let you manually shift at whatever rpm you choose.
If you want it to shift at 6k rpm on its own (while in Drive) get the lighter weight governor kit from A&A.
i have installed many TF-2 kits over the years and have always been able to set the WOT upshift points by adjusting the KD linkage. The governor kit is another way to go
