This is a very rare part from a company called McClure Jaguar Denver. There is not much information about these online, I believe this was a custom piece made by Robert McClure for Jaguar Racing Engines. I've matched it up to an XK150 head we have laying around and the holes all match up. It looked to be used as the manifold looks to be welded, decked and ready to be newly tapped. This setup looks to be for triple carburetors.
Price: SOLD...Or call: (425)-556-0261