Originally Posted by dctraynr

The 777F is based on the 777-200LR, which both use the GE90-110. The 777-300ER uses a GE90-115, so the factory freighter and a 300ER conversion would both effectively use the same engine. The difference is that the 300ER is longer and has more pallet positions, but can't support the cargo density that the F can due (in part) to the 300ER's composite floor beams. The F and 300ER share the same type certificate and probably very similar maintenance requirements.