dont know what the motor may have been changed to but those come with either a B series cummins(5.9L) or a C7 cat (7.2L) used to be the 3126 now its the C7.they have a couple 04 F-750's at my work with 10 yard mcneilus rearloader bodies with 300hp C7's they run pretty good.the C7/3126 has the same type HEUI fuel system as the powerstrokes