I'm not in any way affiliated with this engine... but have been chatting to the vendors as the listing is a bit light on detail.
https://www.ebay.co.uk/itm/267212092789
It's a 3/1 from 1952. Looks pretty complete. No sign of any frost damage!
They're checking whether it turns over for me... will add that info here when I get it.
Looks like a nice resto project for someone. Send them an offer!