Hey there
We do have alot of american cars down here but most are more recent imports. seems everyone is importing mustangs they are the flavour of the month. Most of the early fords and chev etc etc had locally produced bodies which can make them a little different to the body styles you guys had. Then in the later years we had our own locally produced fords and holdens (GM). I reckon the land of the american muscle car might be New Zealand as they imported cars from new, and when i lived there a few years back, there was definatly a lot of american cars there. also sorts of tuff muscle cars.
If you want to talk to other aussies on a forum you can try
www.ozrodders.com it is and aussie forum

By the way the new Pontiac GTO is an Aussie produced Muscle car