I recieved two new box mufflers today for testing. They are same size and specs as the vintage 820 box mufflers. After brainstorming ideas, we decided it would be best to make them more of a solid design (no exit opening). This way the purchaser could use the single casting for either a left or right muffler by drilling (machining) the exhaust exit on whichever side they need. I really liked the image that Steve Miller shared with holes drilled in the top of the muffler. This would have the exhaust exiting straight to the rear with the engine mounted in a laying down orientation, rather than the standing up "Sidewinder" mounting position. Check out the Facebook Group for more details