Aussiespeed® taller than standard finned aluminium hot rod style aluminium valve cover.
The gasket matting surface is machined flat and the 4 retaining bolt holes are drilled.
An engine breather hole will need to be drilled in the position you require to suit your application.
The sand cast material the rocker cover is made from can be easily drilled, threaded taped or even have additional outlets welded to it.
You should always try to keep the breather on the upper section of the valve cover preferably to the side away from direct rocker oil sling.