Tuning for the 6.4 powerstroke is a bit more forgiving than the 6.0 powerstroke. There are tuners out there that are getting an outrageous amount of power. I can create about 250 H.P. without causing any problems. I've seen tuners such as H&S that have 300+ H.P. but I have also seen them blow the head gaskets on the 6.4 which cost a lot in repairs. I would recommend that if you want to run this kind of power you will also need to o-ring the head on these trucks as well. If you are wanting some tuning done on your 6.4 powerstroke or want or need the head gaskets replaced for tuning just give me a call (678) 920-1187.