You would be left with much more money if you just buy an engine setup that way. Several companies stopped making products, heads included for the LT1 because it was an engine that lasted only 6 years, the market was poor and some others already established what niche there was.
So, if a you get someone to spend $500,000 for tooling to make a head for you, you are going to be very broke, because they aren't going to soak up the costs when maybe 20 people would buy them over a 5 year period of time. The reality is, you wont even find anyone to make you a plastic intake, without serious capitol, and there is no way its worth it.