Barracudas were never sold by Chrysler in Australia, seems there are a few that were imported early from South Africa, being left hand drive made them an easy import. There are a lot more US cars these days since they changed the law allowing right hand drive cars (have to be over 30 years old or something).
The aussie Chargers mostly came with a locally built straight six in 215, 245 and 265 ci varieties and there were quite a few 318 small blocks. For a really short period they built a number of 340s too and these are pretty rare and collectable these days. Some other later Chryslers got 360s too but there were no big blocks offered in the locally built cars.
The hero Chargers were the E38s and E49s which had a high performance 265 with triple webber carbs. The E49 (1972) held the record for the fastest production naturally aspirated six cylinder (in the world? maybe just Aus) until the late 80s.