There is a CRS disc brake conversion for FC front end but I wouldn't use it on my own car. Other options depend on your skill level and finances - Torana front ends can be done and there are some big dollar custom made independant front ends available as well. Best value for money, you cant beat a HR front end.
Apart from tunnel mods, you will need a custom length tailshaft and a half chassis kit to support the rear of the gearbox from. Make sure your Aussie box is pre Commodore with hydraulic clutch.
Ken