I did mine three years ago because when I tipped my cuutterbar down I found the head picked too many stones. Reverseing the guards allowed me to cut closer with a flatter knife. If I do pick a stone it sits on the ledge the reversed knives have created. I use air reels which allows you to keep your reels up higher. You have to make a spacer at the wobble drive if you are going to do this mod. Best of luck. Dave