Well it's $8-900 for an air gap, $1800 each for an assembled edelbrock head, MSD dizzy $700, $1500 for a rebuildable 318 core, around 5k for a running 360...you get the idea.
We used to be able to import stuff from the US cheaper than local retail prices but then the government slapped a 10% import tax on us (thats on the item AND shipping) which kinda killed it.
As for the hemi 6 - we got the blueprints and a prototype from the states, but there were a lot of changes made to the bottom end by Chrysler Australia and the original head design was scrapped and we made our own. A handfull of test engines were shipped to Italy for development of the six pack weber setup wich made 302hp@5600rpm & 325ft-lbs@4100rpm.