A Near Perfect Muffler
ERT has a near perfect solution to restoration. The suggestion is to replace the factory muffler with a Briggs & Stratton #291519. The Briggs & Stratton original runs about $43 retail. However, there are aftermarket suppliers with costs ranging from $25. They have also appeared on eBay. The dimensions for the muffler are overall length = 11.25" and the diameter = 3.625". It has 1" NPT that screws into the N62 engine manifold elbow.
You may wish to slip a short section of 1" OD pipe into the exhaust end to provide the nipple for exit through the hood.