These are the green body saws that range from an advertised displacement of 33cc to 42cc. Box store specials that most people consider disposable saws that aren't worth spending time or money on but I have lots of time and these saws are simple, easy to work on and abundant. Good entertainment. Different searches turn up a confusion of part numbers and the general opinion that they all use the same piston and cyl. However, chasing down part numbers, it would appear that there is one basic saw body but 2 different p/c combos. One cylinder has a 38mm bore and the other has a 41mm bore but they both use the same crankshaft, so my question is: Does anyone know for SURE if the larger cyl is an exact fit replacement for the smaller one? How about the Poulan Pro saws of the same size with the nice chromed bore for a replacement fit? Can't seem to find any listing that gives the bore and stroke information for most of the many different models.