I cut the original pipes off a couple inches ffrom the cylinder head (did not remove since I don't have gaskets). Two pre-bent sections of exhaust tubing, a down-sizing coupler, a cheap muffler and a flapper I cut off the stack my dad made many years before (and tacked onto the original muffler. Bent tubes connect and the coupler (squished to fit) becomes a collector. The muffler is welded on top. My Beaver basically has a header on it. Works well with two exceptions. First, when you fire it up cold, there is a small puff of black exhaust from a small pin-hole in the collector; haven't bothered to find and fix it. The second issue is the muffler. If you build one, do NOT use either a glass pack or a really cheap glass-pack shaped turbo. This thing is waaaay too loud. Thought of putting a different muffler on there if I can find one that is sufficiently quiet. When I'm over there again if I think of it, I'll post a couple pictures. I'm pretty sure I never took any when building it some years ago. Pre-camera phone days and all.