looks like an ordinary a14/a15 oval port head...

double post
but ports are quite huge
perhaps its just been ported?

I too wonder maybe it has been ported.

(Most? All?) A14/A15 heads have small water holes, not these large ones:

Cylinder Heads Comparo

ahh but dd if you look closely it appears the water hole may have been drilled, tapped and plugged with maybe grub screws

Yes, I see that. But only three, not four... perhaps someone drilled larger holes in the A14 head, then plugged them, and ported it...

id say thatd be the case
i know that this is done on some of the race motors and hot street motors

The coolant going through there is actually heating the manifold so only good for economy and heating the air for cold conditions.

They also leak like buggery, I plug them on my motors with 12mm wooden dowel.