I am buying a set of used headers and one has a dent in it. If i got a piece of 1 3/4" aluminized steel (i think thats what it is) could i get an exhaust shop to replace the piece without compromising the structural integrity or flow of it?

 

Fill it COMPLETELY with water, and freeze it. The dent will come out after a couple cycles.

 

I might have to try that, it sounds like it would work but if there is any condensation left over on the inside it could rust faster. anybody else have any ideas?

 

you might be able to take it to a body man. They weld on a little stud and grab it with a slide hammer and pop the dent out. It might work if they clamp it in a vise then slide hammer away.