[olddog]

The header pipes end about 8" from the fender, as individual pipes in a square pattern like so ::

The side pipe slips onto the header, as four individual tubes inside the fender. From that point on the side pipes are welded as one piece.

The leakage at the slip joint is minimal. I was wondering if some type of fiberglass cloth could be wrapped at the joint and a stainless steel band could be clamped over it. Of course it would require 8 bands. I was thinking on the line of something similar to a hose clamp only wider.