Husqvarna 392xp project, update on muffler mod and plans for the air filter

[@Metalandwoods_longlostdentures]

How did you come up with 92cc? A 390 is only 88cc. a 55mm bore on a 372 crank (36mm) is only 85.5cc.

[@HillbillyHandworks]

It is a 390 big bore, so it is 57mm and when I did the calculations with 57mm bore and 36mm stroke it was a bit over 91 so I'm calling it 92