ORIGINAL: larry@coyotenet
When the piston goes up and down it rocks slightly due to the side thrust of the rod. The wear pattern of the bore will reflect this, so changing the orientation of the cylinder after it has broken in will reverse the wear pattern. Will require break in again and probably cut life and performance. In other words Not a good Idea! but will work.
Larry
While this is true, it is very small. You will need a mike to measure the differance in wear from front to back and side to side in anything but the most worn out engines.