ive brought mine up to 6k on my 302 redline shifts just dont miss the shift lol and wow mustang gt wounder what happens if you hit the end of the tac . . . . if it blows now we can color it in with a red sharpy . . .jk but thats surpriseing no redline . . .lets put it this way reving the engine fun but dont hit it over 4500 on my engine the max hp and torque is at 4200 i believe on my 302 but every day shifting i dont hit over 2k and wont

 

Here's my $0.02 - generally it is not recommended to rev up to more than 4000 RPM - the oil consumption increases. It is also not recommended to go higher than 6000 RPM - may lead to higher valves consumption. Slightly customized head(s) with stronger valve return springs and polished air intake make it possible to rev up to 7500 RPM. Anyway it's up to driver to choose between crazy truck driving style and buying a sports car, which would fit for racing much better.

 

from experience 4000 aint bad your truck will start shuttin off around 5200
in theory these engines should rev to an infinite number cause there perfectly balanced

 

My tach shows the redline starting at 5700 rpms. I usually don't go higher than 3500 and never higher than 4000, it just seems like too much. Mines the I6 5 speed. Your tranny is most likely the M5OD if it's a 5 speed. The only other 5 speed is the ZF and is rarely found in an F150. The M5OD has vertical and horizontal casting ribs on it while the ZF has diagonal casting ribs.