Ya can't! Easiest way to tell is the iron liner in the cylinder. I/C is iron cylinder, the others are aluminum. Sometimes you can verify that through the spark plug hole. Take a small magnet and see if it sticks to the edge of the cylinder...just make sure it does not drop down in the cylinder! Best thing to do is pull the head! I/C came as all bushing, bushing with PTO ball bearing, or all ball bearing.