There won't be an aluminum head, becase nobody wants to put up the $70,000 to $100,00 to pay a foundry to do a run. Once a run is done, there may be less the 20 people that will actually pay the $2,000 plus cost for such a head.
Improved design. There is a head from Argentina formula cars floating around the Midwest. Big valves, big ports and heart shaped combustion chamber. Mr Dutra himself is rumored to have designed a head. But nothing will happen until the above is resolved.
There are several threads over on slantsix.org on this topic. Maybe you need to revive one.
