There are a lot of things happening behind the scenes, on cylinder head options. Some you are aware of, others you are not, but things will be getting very interesting within the next few months.
We all know how difficult it is to locate an OZ head, and the prices keep climbing, so I doubt these will be available much longer. I looked into having them reproduced, but it was too costly considering all the other options that are shaping up.
The Argie heads will be readily available thru at least one or two suppliers, if not three, in the very near future. The drawback is having to swap headers, if you already have them, as the US/OZ headers will not fit. Even though they incorporate the same port and chamber designs as the US and OZ heads, which limits the flow capacity, they are far superior to the US log heads. The big advantage, is availability, which will lower the end cost to the consumer.
Next is the aluminum crossflow that Clifford has been working on. No one knows for sure if this will actually happen, but I have heard inside rumors that they are still working on it. I don't know if it will use existing headers or if a new design will be required, but did hear they will probably use their existing intakes to keep expenses down. With new port and chamber technology, you can be sure they will out perform the Oz and Argie heads with easy.
Then there is the aluminum Argie head which is already in production, and has been previously discussed in this forum under another topic. I don't know if there are plans to import them, but believe they will show up on the market as well. I don't have any info on the flow characteristics, but have heard they are superior to their parent cast versions. The drawbacks are limited production, which may keep the prices high, even at the current exchange rates, and the need for specific headers.
I am working on an aluminum cylinder head as well. I can't say much right now, but will say that one of the worlds leading cylinder head designers is working on the port and chamber designs as we speak. If all goes as planned, they will be available by years end, at a very reasonable cost. According to him, a naturally aspirated six with a properly designed cylinder head, can make in excess of 300-350HP. I was skeptical of this statement, but considering his designs have won the Engine Masters Challenge, I feel confident he will back it up.
So, hang on to your hats, and get ready for an exciting year. Lots of options are headed your way.