Aussiespeed AS0009 Holden Blue and Black motor 4 barrel performance manifold is not for a mild street engine, the manifold is for engines with modified cylinder heads and camshafts. The widest measurement from the cylinder head face to the widest point on the plenum side is 225mm.
Aussiespeed AS0009 Holden 6 cylinder performance manifold is designed to be used on Holden Blue and Black motor 12 port designed cast iron and Yella Terra 12 port aluminum cylinder heads. The manifold has one x 1/4 npt vacuum take off on the rear of the manifold for brake vacuum and auto transmission fitting.
The FC Holden ran 11 second quarter mile times with an Aussiespeed 4 barrel manifold and a wiff of nitrous before under going a rebuild and swapping to an Aussiespeed supercharger kit