The Aussie heads are the equivalent of a US 351C 2V quench chamber head. In Austrailia the 302C is very common and they all run these same 'Aussie' heads, thus the moniker. The cleveland (as opposed to the windsor 302/351) heads use a canted valve design that has held up amazingly well to constant R&D in the last 30+ years. In the US the manifolds to adapt the cleveland heads to a windsor block (along with the required cooling passage modifications) make running C heads on a windsor block a bit tedious. Especially now that there are aftermarket aluminum windsor heads that flow just as well or better and shave close to 50# off the weight. So the C heads are mainly a swap performed by those who like running something a little different or who want a good flowing set of heads on a budget. In Austrailia there are quite a few manifolds available for running the C heads on a 302 or 351W so this swap is much more common down there.
In conclusion I guess it depends on whether you want a bolt on solution (aftermarket W heads) or whether you're willing to do a little parts matching to make it all work (perhaps while saving a little cash as well).
You can find a plethora of information about the C heads and engines on the following forum:
http://www.network54.com/Hide/Forum/119419
For a 302 the 2V quench chamber heads would be a good combo. For a 351, the 4V quench chamber heads would be a better combo (in a car as light as our cobras).
Mike