Hooker Header Repair Tips and Tricks
I have repaired headers, even though its been dyno proven the dents do not impare performance. You would have to have a severely crushed and collapsed tube. So It was a visual thing for me.
First I braised two straps to the adjacent tube to maintain position. Then I cut out the offending area and fitted a replacement section. Then I braised it together and removed the straps. Braising is less heat(somewhat) and can be done with an inexpensive torch you can buy at the hardware store.