Mr. Gasket 49 Carburetor Gasket Ensures an airtight leak proof seal every time can be trimmed into an infinite number of configurations to modify the port to your exact specifications Engineered specifically for 2 barrel Holley carburetors from 300 to 500 CFM Provides optimum torque retention ideal crush resistance and excellent sheer strength and seal using minimal clamp force yet still releases easily every time Manufactured from a durable heat resistant and fuel resistant composite gasket material and die cut for a consistent precise fit and years of trouble free service