Seen your post on that site upon which I will not post.
re your exhaust problem, its possilbe to remove the dents from inside the pipe by pulling through an egg shaped former.
I am trying to find an article showing how its done,which I will post up.
It is in french but with lots of photos and diagrams.
Be patient please
Far better and more satisfactory than replacing with pattern items; or filling with braze. My 1928 'beam still has its original exhaust, and with original innards in a new made silencer.