Can anyone tell me what this engines possible origin could be? I have a h89 head but this has nothing but nissan and Japan in the casting with nothing else. It has the twin carbs and dual outlet exhaust manifold. I was pretty happy when I saw the size of the ports, 37 x 29 approx. Any info would be great.

Thanks for that Dundee, I haven't taken the head off yet but hoping it's still in good nic.