I'm surprised that no one lined up the dyno's from a 3rd party source....take a peek what comparing two dyno's from K&N filter show:
You will see that the 3.5 makes far more HP & more Torque than the 5.4 and it makes the same HP at 3,400rpm (roughly 250 HP) as the 5.4 peaks at, at approx 4,600RPM. So the 3.5 equals the PEAK power of the 5.4 at over a thousand rpm lower.
Then you will see that the 3.5 equals the peak torque of the 5.4 at only 2,500rpm compared to the 5.4's torque peak coming at 4,500 rpm. So the 3.5 is producing the same torque at over TWO THOUSAND RPM less!
Pretty convincing that all the talk about "it runs hotter, spins at higher rpm so it won't last" is just wrong. The 3.5 will equal the 5.4 in every way that matters at much lower RPM's than the 5.4 and of course will provide a huge reserve of power over and above what the 5.4 produces at it's PEAK power!
No sense arguing about it....the 3.5 is a far superior engine as far as the power and torque it produces.
If you don't like the 3.5, even if it's just because it "makes you nervous" then that's fine so own it and be proud of your position but don't be mislead by hype and pure BS when the facts are available for anyone with a brain to find. Research before you make your decisions, don't ever rely on what some guy said....
My opinion is based on owning two 5.4 expys and well over 300K miles for the past 15 years and I bought my 3rd ( '17) with the 3.5 last November. The 5.4 is noted for leaking headgaskets, oil leaks from left side rear head, inability of Ford to keep the sunroof dry on the passenger side of the glass<LOL> and a host of other issues but it was also a strong, faithful truck(s) for many years. So I've got no axe to grind either way....I like the 5.4 but the 3.5 is just plain better to me, by a wide margin.
jeff