Aussiespeed hand polished cast alloy oil cap cover designed to slip over after market chrome push in style breather caps matches other finned products for our Valiant and Slant 6 finned products. The cover 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.