This is an original GM high performance aluminum intake manifolds for Big Block Chevy engines with rectangular port heads and a Holley carburetor. The casting number is 3866963 as shown. The 3866963 intake was used in the 1965 model years only on the high performance L78 396/425HP engines. The casting date on the underside is 3/15/65 which obviously can not be seen when installed. This is a very hard to find production dated 3885069 intake. This intake is in very good condition as shown. It is in bare aluminum finish with no paints or coatings and looks more like a piece of jewelry than a mechanical part. The part number,…