Identification Needed for Cyl Head

[SCHWANGAU@aol.com]

I scraped more rust and grease off the head and found a stamped number:
511538.
This does not appear in any Spitfire parts book I have looked in.  Can anyone
help me?  

The head has six ports and fits on 11 studs.  Apparently not an early
Spitfire head as I thought.  Is it Herald?  Maude?  Hubble? Saturn V?  

I would like to identify it so I can find a user who needs it.  I'm trying to
reduce my unused spares pile.

Any help is appreciated.

Brian N.

79 Spitfire
65 Spitfire
59 Bugeye
63 Consul Capri