Actually, the measurement from the Wall to the middle of the Bolt is 14 inches. I don't have a clue what size I currently have installed. The house was built in '70 -- thus, enough room for a Large Tank, which is probably why the newer (but not so new now) tank sits 2 inches or a tad over 2 inches from the wall. So, if I am understanding what you are saying, if I should get this New Kohler, it will sit even further out from the Wall -- like around 4 inches ??