[1985 CCX]

So here is the breakdown

Headers collecting outside require fishing them outside car body thus easy does it. Watch that paint!
Inside slight easier process I feel, more of an alignment less paint issue.

Pictured
Pipes from outside vs inside
Header pipes, as well on the bench together.

I think custom headers can be challenging. I just get it in my thick head, take your time as its going to come out better.
Planning a header outside the body step by step when I start it...