I'll upload a cross section of the head (it replicates the engineering drawing on wiki). It uses the standard pushrod length and angle. To actuate the inlet valves it needs an additional rocker shaft added on the other side of the pushrods.
From my model the pushrods are almost the only thing that you can use apart from a few rocker pedestals.

I have printed a cross section of the head, including valves and rockers etc. Bolted it onto a block and had the valves actuating. That’s about as far as I have got.

With regards to casting, technology is progressing very quickly and with 3D sand mold printers being used for R&D and low volume parts - it all might be achievable!

Have you seen Derek from Datsun Works Twin Cam L Series head? His heads have been cast using the 3D sand printer technology
http://www.datsunworks.com/Blog/