In the Neverending quest for more power, I addressed the air intake on the 5.4. The bean counters at Ford won, and had the engineers install the same air box on all F150s except for the Lightning.
The factory air box is too small in volume to properly feed 5.4 liters, and the inlet opening is smaller than the throttle body. First, I tried the 'Gotts Mod' and found that I gained about 3-5 g/s with my mass air flow reading at WOT. This should be roughly a 4-7hp gain. Still, I felt things could be improved.
In my reading, I found that the Ford Lightning did not share the same air box as the other trucks due to its higher air flow needs. This box has roughly 2.5x the internal volume, a 3x larger opening by area, and places the MAF away from the walls to help prevent stagnant flow around it.
I cut up the factory tube to reuse the connections for the IACV and breather, purchased a generic 3" cold air tube kit, and a Lightning air box. From there, I cut the inner fender opening larger to match the snorkel dimensions of the new air box.
Once it was all installed, I logged my MAF readings on the same stretch of road as before and found 10-18 grams per second increases over the Gotts Mod! We are looking at another 15-20hp gain, and the truck feels much stronger at all RPMs.