Crankcase Evacuation System, Weld-On, 12 AN Hose / Air Oil Separator / Breathers / Fittings / Check Valve / Nipple Included, Valve Cover Fittings Required, Aluminum / Steel, Natural, Universal, Kit. This system mounts along the firewall and connects between the valve cover and the header. Tested by engine builders in the Midwest, this will create vacuum pressure in the crankcase, reduce windage, lower oil temps and can free up to 7 horse power!