Jim is right the case is back wards . If you had the sleeve out you can tell by looking at the height of the holes in the sleeve , the intake ones are lower than exhaust. Some rods were also offset to clear the counter weight. Some rear covers only go on one way also, have a recess to clear the piston at bottom of the stroke . The baffle is on the intake side to direct the fresh fuel charge upward & not out the exhaust. MAX H.