Inlet Needle Steel Seat Adjustable HolleySteel tipped inlet needles are necessary when using exotic racing fuels. A . 097 inch seat size should be used for small four barrel carburetors; a . 110 inch seat size should be used for carburetors up to 735 CFM; larger seat sizes should be used with carburetors 750 CFM and larger. The following steel inlet needle and seat assemblies are available from Holley. Features and Benefits: Compatable with alcohol, benzine or acetone additives Adjustable