Tom Langdon, a retired GM engineer, may have what you want; he owns the tooling for the cast iron reproduction "NICSON" headers that Phillips Performance developed. He has built tube headers in the past; the cast iron headers that he sells are of excellent quality. He'll want to sell them to you, but he might help you design your own. See the Stovebolt Engine Co. link on this site.
God's Peace to you.
d
Inliner #1450
