I have no idea but there is a Twin cam head available for the I6's just cant remember the name. Ummm The guy that does them is from Townsville I think??? Was featured in Street machine a few years back. Will have a look for some contact details if anyone is interested.
Bob Krogdahle is the dude in Townsville ... I paid him a vist a few years back when he first developed the twin cam heads for the AU. He wanted 2.5k for a simple head convesion without any performance gear (excluding labour) or 6k for a complete rebuild (i ended up rebuilding it single cam). It also has "only" two valves per cylinder whereas the BA heads got 4.
Anyway back to the point, the BA heads do not bolt up due to the stud bolt pattern. Another prob would the engine management. The AU computers are not designed to handle VCT applications, however an aftermarket system could take over easily. Last but not least, a problem arises is the timing gear. Hope it helps
If u realy realy realy want a twin cam in ur AU (i presume its an AU), u myaswell do and engine transplant (with wiringloom transplant etc). Much easier and quicker