I have been reading about the fuel system shim idea you guys have been using. 6L out of the box run about 43 psi and spec is 45. What I have been doing to correct this is replace the regulator pintel oring with a new one but installing it backwards so the tapered side is facing the filter housing. I cant see why this wouldnt work on the 7.3L. After doing this mod fuel pressure is usually in the area of 60psi. Just thought I would throw that out there!!!