RE: Hangar 9 P40B Warhawk 50
Sorry I will not have access to those planes for a few weeks ( storage ).
The "can" mounts on the firewall or where-ever you can affix it.
I used small clamps to affix auto tubing between the four strokes normal header without the muffler.
Your only big concern is that the exhaust tubing must be able to sustain higher temps. That is why silicon is normally used.
By the time the exhaust passes the header, it is not still being burned, so it does not tend to scar the silicon tubing.
Automotive tubing used around exhaust manifolds also have to take high heat so it works well.
Check into things used for tuned mufflers too, as they have the same routing problems with their tubing.