The worst motor IH every built for Ford was that pos 6.4L...
Every single problem with the 6.4 can be traced back to the emissions equipment. The diesel for the DPF is injected into the back two cylinders on the exhaust stroke, some of it washes down the walls, diluting the oil, and messing up bearings and rocker arms. Also, Ford was recommending very long oil change intervals. Once that crap is dealt with, the 6.4 is just as reliable as any other modern diesel. One of my buddies is a farmer and he's put almost 300 K miles on his with no problems. Mine was deleted at about 65K miles when I got it and the dealership I got it from had records for semi-synthetic oil changes every 5K miles. I had a mechanic go through it with a fine tooth comb and it hadn't suffered any damage so I bought it. The DOC and DPF went safely into the barn, I put on a straight pipe, a DPF-R+ tuner with a pretty mild tune that ignores all the emissions programming, and a coolant filter. It pulls a 16K lb. equipment trailer and my toy hauler RV all summer. This thing makes so much power it is scary, and gets about 10 MPG pulling the RV. I registered it as a commercial motor vehicle under my own DOT number so no emissions checks.
I have been intrigued by the new Ford 7.3L gasser. My 6.4 makes double the torque, but it isn't going to last forever. According to the youtube crowd, there is a ton of power potential with that 7.3L gas, and the ten-speed tranny is evidently a jewel. That may well be my next rig.
