The Meteor 661 cylinder certainly doesn’t run like the OEM. I picked one up to experiment with a Wiseco Piston because the Meteor plating is harder and the Wiseco ring at the time was too hard for Stihl plating. It was about 25% slower than an OEM cylinder. Might better have been dragging around an 044 that weighed 3 pounds lessMaybe meteor ? All my old saws say Mahle but new say stihl ! I bought meteor cylinder for 661 and looked identical but did not say stihl