I need to make a curved header for my 20 size engine with an oval exhaust port. Can anyone help me with whats involved, what materials to use, who to contact for welding, or bending? I can machine my own flange, I just need help with the tubing end of it. Its an old motor and nobody makes one I can buy or modify. I thought about buying a pre-made one and cutting off the flange but this leaves me short on size and in the pocket. I just think making one myself might be cheaper and have just as good of a result from a purchased one without too much trouble.