Part# AS0241 - AussieSpeed 4 barrel intake manifold plenum filler. We made this piece specifically for fellas who have our AS0016 and AS0012 4 barrel race manifolds fitted to engines that are really closer to a street type cammed engine and are operating more in the low and mid rpm range, like for example the street stocks on pump grade fuel with intermediate gears where they run from 2200rpm up to 5500rpm with moderate compression ratios. Adding this plenum filler helps the bottom end pull out of the corners without hurting the top end breathing too much.  They look fairly simple enough and ugly, but the shape and placement in the manifold has been developed on the flow bench to give us precisely what is needed.