The "inboard" clamp and 5/16 bolt securing the horizontal distrbibutor bases (Cub and Super A) gives me fits when ignition timing requires adjustment...there's simply very little room for wrench-turning...especially on Cubs. I bought a 1/2 inch, 12-point combo wrench and cut away the open end to make a short-handled wrench for this application but it's still difficult to use. Does someone know a trick or special tool that can be used to loosen and re-tighten this bolt?