I ran a 20 on one I had with a muffler mod. Wouldn't go any larger.
Awesome! Let us know how it runs. I have a ported 395 as well and love it. Strong saws and smooth.
If you don't mind the price tag Stihl's isn't as tacky. I ran it for several years but switched to Husky oil as it was a little cheaper. More...
I am a sucker for big saws as well. Got to a point where I have 4 or 5 big ones and no big wood to cut! Nice saw.