As gkaraolides wrote Peter Billes designed the Webra after the HP. I always figured this gave him an opportunity to fix any issues he had with the HP. They are both outstanding engines some of my favorites.

If you do need a strap on muffler BCM does offer them. The work great on all the engines I have tried them on. Later both HP and Webra offered bolt on version that used the same bolt pattern as the OS #744 muffler.

turbo