500 CFM Carburetor for Small-Block and Big-Block Engines with Either Dual- or Single-Plane Intake 75305971OE Number: 1903 500, 1903 Will Fit Following Models: Small Block and Big Block Engines with Either Dual or Single Plane Intake Manifolds Specifications: Repalce 1903 500CFM Carburetor Flange Type: Square Mounting Hole Quantity: 8 Body Material: Aluminum Spring Force 5" Hg (Orange) Package Including: with Mounting Hardware Package Includes: 1x Carburetor