Each Edelbrock Chevrolet Cylinder Head is MADE IN USA for great performance and high quality! Cast and heat treated at the Edelbrock Foundry and machined at Edelbrock’s manufacturing facility in the USA, Edelbrock Chevrolet heads are the best in quality and performance. With outstandingly efficient ports and cutting-edge combustion chamber shapes, Edelbrock cylinder heads deliver better performance across the RPM range for terrific throttle response and premium horsepower. Outstanding features include threaded inserts in rocker stud and exhaust bolt holes for excellent strength and durability, as well as manganese-bronze valve guides. These are things that some companies just do not deliver!