I might be wrong, but I seem to remember my 16SS having the two rear mounts on the transom plate, and a single front mount. The last set of photos are all V8 mounts (4 points). All of us had a first time doing this, I took lot of measurements and pictures along the way. I'm helping a friend redo a x-16, it's a merc 140, I could take a few pics of it.