【Electric Choke for Automatic Start-Up】 Comes with an electric choke for fully automatic cold start management, perfect for daily drivers and consistent performance. 【Optimized Annular Booster Design】 Improves idle quality and eliminates throttle hesitation with evenly distributed fuel through eight-orifice boosters. 【650 CFM Square Bore Configuration】 Provides strong airflow for small and big block engines, compatible with both dual-plane and single-plane manifolds. 【Stable Aluminum Construction】 Lightweight diecast aluminum body resists corrosion, deformation, and thermal stress for long-term durability. 【Direct Replacement for Edelbrock-Style Units】 Compatible with square bore setups on Chevy C/K series, Suburban, P30, and more. Plug-and-play install with included parts. 【Technical Specifications】 CFM: 650 / Barrel: 4-Barrel / Flange: Square Bore / Choke Type: Electric / Finish: Satin 1906 AVS2 650 CFM Electric Choke Carburetor 4 Barrel Square Bore Carb Replacement with Annular Booster for Chevy Small and Big Block Engines