Looks like GM/Holden may have an answer.
http://theage.drive.com.au/motor-new...218-1ayxg.html
"The new engine tipped to be fitted to HSV's new range by 2013 is expected to be based on the engine in the wild Chevrolet Camaro ZL1 that was unveiled at the Chicago motor show.
With 410kW of power the new supercharged 6.2-litre V8 delivers 26 per cent more power (85kW) than HSV's most powerful cars on sale, the GTS and Grange, and almost 10 per cent more than the most powerful Australian-made car ever, HSV's limited edition W427."