I've had this Granberg for probably 3 years and never have used it until today. I decided to give it a quick run, just to see how good, or not good, the 660 could go through it. The fat end is 2 ft and the small end is 18 inches and it's maple. The dark spot is rot unfortunately, but it doesn't go all the way through. Thankfully, I have a fella on here building me a ported 394, because the 660 is lacking power for sure. I may even invest in a 3120 as well, because I was pretty shocked at how slow a go it was. I know the stock 660 isn't heavy on the wow factor, as far as power compared to ported 394's/5's, or 100 cc plus saws, but still. This isn't that big of a chunk of wood either. Even with that said, I'm happy to get this going and start cutting slabs. Seems to me, this could become pretty addictive.