This is an original GM cast iron intake manifold for Big Block Chevy engines. It has large oval ports and a square bore flange for Holley carburetors. The casting number is 3866948 as shown. The casting date is F 23 6 which decodes as June 23rd, 1966. The 3866948 intake manifold was used on many 1965-1967 396/325HP, 396/350HP, 396/360HP, and 427/390HP engines. Please confirm your specific application. This intake is in very good original condition overall. All casting numbers and marking are intact and easy to read. There is no significant corrosion or porting. I see no breaks, modifications, or repairs to this intake. Don't miss this awesome original GM intake manifold. This is your chance to own the original GM Big Block Chevy intake manifold you have been dreaming about at a GREAT PRICE. Don't Miss Out! Check out my other listings for more rare and hard to find parts.