Just blew up my 97 MXZ 670. I have three 670 motors to take cylinders from. The two best cylinders are stamped with a "2". All three sets of cylinders came with a cylinder stamped with a "1" and a "2" Cylinder. I looked them up, and all 6 cylinders have the same part numbers. Is there a deference. Can I run two number "2" Cylinders? They look the same. If they are interchangeable, why did they mark them?