16V 4AGEs can now use a 20V header!  The new 20V header modification service has been added to the catalog and can now be ordered like any other SV3Power part.  You can send in your 20V header for modification to fit your 16V engine, order a special extended version of the 20V-to-AW11 adapter downpipe, and replace your old cast-iron manifold and rotten stock downpipe.  Click here to see the header in our online store!