i bought these D1ZE heads here in Adelaide, Australia
(American-made 4v Heads) They are open chamber heads with the big 4v valves.They were being used on a ski-boat engine apparently.
They cost about USD$400 from our local 'Gumtree' online marketplace (our 'Craigslist')
These type of closed chamber heads were not made in Australia; we would've had 2v inlets on our locally manufactured, equivalent heads.
These will go on my George Pence spec engine i'm slowly,starting to get started. A Clevo block i bought for USD$40 has been tested as original bore size