I have 11 saws that have been ported by Terry in Des Moines, IA and he makes them very torquey with lots of usable power throughout the power band that just about pulls you over the log you are cutting, LOL, most that use his saws like to see how hard (and wrong I know) you can push on one and not stop the chain, LOL.
That I know of he ported one of the first 441's in the country and i ran it for a couple of years before I smashed it and got more of them. He has then done 3-4 for me and one or two for Porche and some for others. My timber cutters that have run 660's and modded 660's at that for years will only run Terry's modified 441's with 28" bars on them. As Porche's video can attest to, the modded 441 with the larger factory oiler has gobs of power and runs and handles like a Cadilac, it has no flaws. I have run 441's for weeks sun up to sun down and never had any hand or wrist problems. I have then run one of my modded 660's for a few hours and they about wreck me, next day can't open my hands and such, and they aren't faster than the modded 441, and they won't cut anymore wood until you get a few lengths past a 28" bar.
We log and can't really justify owning the 660's anymore, because with a 28" bar the 441's are cutting 50"-60" oaks as fast or faster, when you figure limbing them, with the modded 441, and the fuel mileage just makes more wood fall faster yet in a days or weeks time. The modded 441 is the reason I have no use for a 460, a modded 460 has the same power, but they have as bad of fuel mileage as a 660 and the same vibrations and air filtration.
After using one of Terry's 441's for day, my best cutter was quoted as saying, "I'd walk a 1/2 mile past a modded 660, everyday, to run that 441".
Terry's work with the 441 over the years has really made him an expert on the several different ways to get the power out of the 441 from the carb to the strato cylinder and piston to muffler, and they behave like ##### cats without being tempermental to start, idle or use. While everyone else was crying that the Strato's were junk and un-moddiable or hard to modd or you couldn't get any gains out of them, Terry was doing it. Its the same for the C-M version, while others were saying you can't modd them. Terry had it completely figured out and knows ways of making it even better.
My two cents on the modded 441,
Sam