LOLROFL. Yeah, let's find someone to spend a kilodollar for a garage monument (part that isn't really useful without the rest of the parts to go with it, and even then, probably not). Pretty good odds it might not even properly bolt up to any production gasoline Slant-6 engine; a
lot of changes were made for the diesel project. Detailed info
here, including pics of that same exhaust manifold or another one like it.