Hrm, what do we have here? FMS 24lb , EV6, 6-hole injectors. The one on the bottom is a factory replacement EV3, 4-hole injector. Finding contradictory information as to if these will be any improvement or not. If there is any improvement, awesome. If not then oh well, with the amount of miles on the truck the injectors could stand to be replaced. I imagine if I do get any improvements it will be due to comparatively fresh injectors rather than being a better injector. It is not a 100% complete unbolt, bolt back ordeal; just need to get some adapters in order for that.

FMS EV6 on the left (bottom), factory replacement EV3 on the right (top). Again, I do not know why Supermotors has turned the picture 90* left. You can clearly see how much finer the holes on the FMS injectors are compared to the factory replacement.

Better shot of the difference in connectors.

Picture showing size of the adapters needed. Ford Motorsport pn FMS-M-14464-A8.

Whew. Close. After getting all the injectors in and rails bolted back down I did not think to check for clearances. This is cylinder number 5 (driver side front). There is just enough room between the rail and ECT sensor for the plug and adapter and just enough slack in the harness to plug back in. All other injectors were fine.
NOTE: I did not pull the upper plenum to install the injectors. Doing so would have made it massively easier to access the injector rail studs but ultimately more work. With a universal and long extensions the swap can be done with a bit of patience. The only things I pulled off the engine were the throttle cable bracket and TPS. ECT, IAC and CTS were all unplugged for more play in the wiring harness to move out of the way.

Installed! Just as easy and straight forward as you think it is.