Some other items that will need to be designed are the cam drive/front cover assuming DOHC. The oil pump drive will need to be addressed as well since it runs off of the bottom of the distributor. With the stock cam removed the lifter bores would need to be blocked off to maintain oil system integrity.
As far as casting goes if you have unlimited CNC resources then fabricating the patterns can be done. You will need to find a good aluminum foundry to do work with. The foundry can advise you on where the risers and vents need to go.
Most likely this would take 2-3 itterations before you have castings that are good enough to start machining.
Once you have the head casting ready, then comes the entire valvetrain which most likely would be custom designed. Also the short block would need good pistons and rods to support the target rpm.
Rough estimate this will be a 3000-4000 hour project before your done to the point where you have a running engine with enough testing to validate the design with parts ready for production.
Consider the time investment, is this a one off or are you considering producing parts? Then the ROI has to make sense with a target sell price that folks will pay. If its more than $2500 for a complete head with cams most likely your market will be under 20 set.
For now a one off(maybe a 2 off for a friends 240z) is what I am looking at. I have always been a "DIY" person. Hopefully with my bosses and other faculty support. Just the satisfaction of poping the hood at autocross and people seeing a "24v DOHC EFI" straight 6 that revs to heaven, and when they ask me where I got it "oh, I built it."
As for cam gears I plan on finding a nice sized timing belt and making some pulleys on a CNC.
Did not consider that the oil pump runs off the dizzy any ideas?
Valvetrain, there was a smallblock chevy with lotus designed 4 valves per cylinder in the 90s with very a similar bore to my 230(smallblock bore = 3.9in, 230 = 3.875 + .030((for rebuild))) I need to do some checking but I could design the Head around those valve sizes.
I am still in the "is this actually possible" phase so I am trying to gather as much info as I can.
