If you have access to a mill (CNC prefered) you can build the cylinder head in layers and save the $50-100,000 to have one cast. Mill the combustion chambers in one side of a chunk of aluminum then mill part of the ports and water jacket in the other side. Build the other half of the head from another piece of aluminum. Practice on a piece of oak lumber to work out your layouts.
Good luck and have fun.
Ron
