Dave,
I don't know if you are trying to do an authentic old pattern build but if you are looking for a custom header have you heard of Mueller headers? I have seen pictures of his work on the NSRCA list and they look like art work. If you give him the engine brand/type and rise info he has it done in a matter of days. If Dave G. doesn't have his contact info I will dig it up for you if you decide you'd like to talk to him.
JLK