Originally Posted by Ridin' Green
That line is not true at all. I've been cutting for 30 years, and I've used a lot of saws over that time. My smallest is my 45 cc Jonsered 2145, and it pulls my 18" bar with no problem even in oak with the bar buried all the way. In softer woods like maple or pine, it does it with ease. I ran an 032 Stihl (51cc) for 20 years with a 20" bar, and it was never lacking power either. An MS 250 is alll the OP needs for his intended use if he is wanting to stay with Stihl.
This is not a 'line' it is an age-old rule-of-thumb to size a chainsaw engine to a bar length. I put myself through college by working in a variety of lumber companies and have been running chainsaws for decades as well. Your 032 could pull a 20-inch bar but it will do so at a far slower rate than a 361. I am sure your 2145 could cut hardwood with a 20-inch bar but I will be done and back home with my 460 while you are still working.