@Dipstick , even with the FDC bypassed, the engine will happily burn the full variety of fuels (but without the FDC it will not try to compensate for varying energy density; the truck will feel fine with Diesel and feel like having more or less power with other fuels, depending on the fuel used). Bypassing the FDC is cheap insurance against oil dilution.
I am driving a "pretend bobber" right now (interaxle driveshaft between the rears removed) and while I do not notice a power increase, I do feel that it turns tighter than before.