I put a 360 lower cowl with scoop on my 320 powered RV-8. On my installation, the center of the scoop inlet sat 1.75" lower than the center of the inlet to the FAB. Instead of lowering the carb / F/I Unit with a spacer, which may alter your cable runs, possibly cut and re-glass the forward portion of the FAB with a slight downward angle to line up with the scoop inlet. I had to do this and it has been working just fine. The potential benefits to this are that the FAB will not rub on the lower cowl, which may cause the upper FAB mount plate to crack. The other benefit is that if one were to put a 360 in afterwards, the cowling already fits.