I am looking to swap the engine on my car to a newer/more powerful one, I have heard that all the e-series engines are interchangeable, does this apply to the AU? I just screwed the head on my reco ED falcon engine that was only 7 months old. Any help would be appreciated.

With a few small mods you can put an AU engine in if anythign go an AU bottom end. Stay clear of the AU head im told by a few major blokes (eg Jim Mock, Brendon Mock, Varies Other power upgrade places). If anything grab a EL head. Also the AU bottom end is stronger and is a better design for all forced induction (so im told).