Formerly new missing the OEM box - NOS GM correct fitting AC Delco exhaust manifold heat riser butterfly control valve – P.N. 3731396 – original OEM with the “TOP” stamping - factory OEM for 1956 Chevy passenger car with 2x4 carbs as well as 1956 Chevy Corvette - may fit other makes and models as well - we are not 100% familiar with all items, it is up to you to verify part number and pictures against your application – very dirty and sooty stained former GM dealership inventory in vintage NOS condition as shown - never installed – some light surface rust from sitting in storage so long – moves nice and smooth