I know they produced Y-Blocks in Australia for a lot longer than we did. I also know that South America produced them as well.
The two center exhaust ports were always a major heat problem. The gasket set I got from FelPro had 'steam holes' in it. They suggested I use the new head gasket as a template to drill holes in the heads and both block decks for better cooling.
In S. America (Argentina, I think), they came up with a new head, similar to a 289 head, with the center exhaust ports re-configured.
My '55 came with a 272. I still have it on a stand. It's old and tired but original.
I admire all you guys down under, for making things work from zero resources. I love stories like your Y-Block story. That copper wire was the best heat conduit your 272 ever saw! - Dave