Can I raise the motor RPM's with a stock 05 FX4 f150 tranny?
 

I was thinking if and when I build a motor for my 05 FX4 screw...maybe I would build it so it can handle some more rpms (if I get cams and ported heads for it). Can the stock tranny take more RPMs...does it even matter to the tranny?

The stock tranny limit is 5400 rpm. If you exceed that, you can balloon the torque converter.

Gotcha...do you know off hand stock rev limiter on the 05 fx4 with the 5.4

I think it's 5200.

The 5.4 is a torque motor, not a high end HP motor - you shouldn't have to bump it. If you do, you need an aftermarket TC.