pictures of pedal assemblies 340 vs. others

In the old DC manuals they suggest adding 0.75 " to the arm to the z bar as to accomplish a similar effect . They didn`t specify which pedal system 5.25' or 6 ' so I assumed both would benefit from the longer arm . I modified a 68 318 set of pedals ...
I assume that adding this to either arm ( the one to the clutch fork or the one to the clutch rod) would work, or does it have to be on a certain one? Thanks!