Let me throw this out. Say you got a 4 or 5 speedmaster on a box or a bravo and a stellings box. If your close to the transom and are running a short driveshaft, These mounts will allow an up/down adjustment to help reduce u joint angle when moving the box from the middle to eitjer the top or bottom holes. (I'll measure and picture the amount of adjustability if anyone's interested) safe to say at least 1/2 inch in either direction.