What HardcoreB and I found was that the runners are EXTREAMLY short for just about everything. We had the luxury of 8 runners and 8bbls, so he was able to point them pretty easy where we wanted them.
The spacer was for both plenum volume and giving the fuel/air some height to make the turn.
6bbl would probably benifit from the height, but aiming the runners would get complicated.
