At 170,000 mi. I did several engine modifications on my 06 f150 4x4 5.4 3valve, including phase 1 cams, short headers, hi volume oil pump,phasers and timing chains, modified intake [4"]. I had little power gains until I added these injectors. I use the truck to tow my camper and a flatbed w tractor quite a bit so it would bog down on hills, It's still not as powerful as a deisel
but it doesn't cost near as much to operate and maintain. On the hills I gained about 15-20 mph depending on the grade.
This mod is part of an overall project including 4.10 dif and new tranny. I didnot do the bottom end as everything is in good shape. The fuel milage sufferes however but I'm not looking for milage.
Bought the FoMoCo/ Bosch injectors, because I didn’t want issues with cheaper knockoff replacements. Had read some reviews on forums, that cheaper replacements were trouble. These are individually packaged and very nice. Premium quality, 4 hole Bosch injectors. Can’t wait to install them.