Aussiespeed cast alloy oil cap cover designed to slip over after market chrome push in style breather caps matches other finned products for our Hemi and Slant 6 finned products. The cover is shot blaster satin aluminum finish that can be painted, polished or treated to your own custom finish. is supplied with chrome push in breather cap base part # AS0035. As this is a cast item there is taper on the internal dimensions. measured in the centre 42mm deep, 37mm outer inside edge. 72mm inner opening diameter.