Holley 0-80541-1 Model 4150 High-Performance Series 650 CFM Square Bore 4-Barrel Mechanical Secondary New Carburetor 4-corner idle system for precise control Provides maximum air flow and reduced turbulence Dichromate finish with double 30cc accelerator pumps Button-head throttle plate screws allow more air flow Includes power valve blow out protection, notched floats, and jet extensions