The 241 is bone stock, and he won't let me touch it! Wants it to stay quiet, and it cuts just fine.
The 462 was ported by Dr. Al and runs really nice.
The 660 is an Asian clone with a Cross P+C built by yours truly. It has a base gasket delete and timing advance and runs very well. I purchased 2 Cross P+Cs that were nearly identical and both ran very strong (I called them my Asian twins). One went to my brother, and the other to my friend next door. Both are still doing well.
My brother sold his MS460 to buy a Dr. Al ported 462 after he ran mine!
I built the Clone 660 "twins" years ago and tested them on that large, dead Chestnut Oak log I was cutting in the winter. The mufflers on the Asian 660 kits are pretty free flowing but have a baffle. With one saw, I just drilled a 1/2" hole in the back of the baffle, in the other one I removed the baffle completely.
The one with the baffle removed sounded better and seemed to have better throttle response but died in the cut when doing that Chestnut Oak. I replaced that muffler with one modified just like the first saw and the power came back in the cut. The difference in torque was significant!
I subsequently played with the exhaust on some of my ported 660s, but they all did better with the baffle removed.
I have concluded that a saw just runs best when the muffler matches the porting (etc), and experimentation is the only way to know what that is.
It was like my carburetor experiments. My Dr. Al ported 460 was 10% faster in the cut (Hickory) with an HD-50 (461) carb than with the 460 carb. My other two ported 460s were both slower with the HD-50 carb. I cannot explain why, I just went with it. I kept the Dr. Al ported 460 (which ended up being the strongest) and moved the other two along.
I remember a guy in HS had a freaky fast 396 Chevelle, but it wasn't good enough for him. So, he sold the 396 motor to buy a 427 motor, and no matter what he did to it, the car was slower!
When you find lightning in a bottle, just keep it!