I have since pulled the liner to check for that-again all though, I felt pretty confident there were not any burrs. Yes, it was the S 61 K. The ring could only go on one way, given the pin in the piston. And, I did use a piece of the old ring to clean the groove. Now, I finally found my 'lost for years' Higley book on engines who said: the piston ALWAYS goes in from the bottom! I put mine in from the top-seemed to slip right in. Seen, and worked on, larger engines where you get the ridge build up at the top-didn't seem to be the case here though. The ring I got was from Tower. BTW, sleeve looks O.K., the engine was just above idle when it seized. I ran the engine only in short bursts for only a minute or two each time-though the engine was, IMHO, way to hot, despite running it rich.