This K&N Stubstack is designed to be used on Holley 1050 & 1150 CFM Dominator carbs. Will not allow use of a standard air cleaner housing, but it will hold down the base plate of a cold air scoop. Designed to straighten airflow and helps even out the flow to all four venturies. Decreases the restriction around the throttle bores. The K&N Stubstack is designed to increase the airflow of carburetors by decreasing the restriction around the choke horn. The stubstack fits inside the air cleaner housing and slides snugly down over the choke horn.