patrat. yup.
the book also explaines about 4-2-1 headers. but my fingers hurt now...lol!

Ya know that big single flange on the broadfoot one seems like problems just waiting to happen. Couple that with the other flaws in the design and the same price as well as the reputation Broadfoot has with being really slow about actually getting things to people, I'd stay as far away as possible from those.

Edit: I didn't see your post before I did mine Bill, oh well it's there now.

As for copying them, don't forget you're going to need a TIG setup too as well as knowing how to weld so plan on another $1500 minimum as well as sourcing 347 filler rod which is necessary for welding 321 and a right bastard to get in smaller quantities. (Ask me how I know, I've been fixing cracks in my factory header).

I think there is a distinction as well between copying a design if you're making it for yourself vs. copying it to make for other people. Given the materials and know-how involved, if you've got the stuff to make it, you probably have a pretty good idea how to do it anyway.