Get silicone water heater hose at Napa auto parts or Delta rubber if you have a store close. It comes in sizes from 1/2" to 6"ID, Get the tripple ply if you can. Then cut your exhaust inside the cowl and slip it into a piece of hose to fit your exhaust. After cowl is on install the pipe piece Super easy cowl removal. Use zip ties to get a snug fit. Been using the stuff for years.