I want to get a cast iron turbo exhaust manifold copied. The stock ones, made by HKS in Japan, have a tendency to crack when used on track. I don'tbelieve the design to be at fault, more likely a material problem. I have been told a high nickel content cast iron is better, can anyone recommend a good material spec or otherwise advise on what i may need? Is there an alternative to cast iron for casting such items? I will only be wanting about 6 made, no big production run! Cheers. Photo of what I want to copy is at http://chriswilson.tv/manifold.jpg
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