Nobody was able to help but now I have it off. For future reference the sail drive sea cock for an SD40
has 1 inch BSP threads. The adapter I got was not long enough to let the ball valve clear the bell housing so I needed a coupling and 2" nipple as well as the elbow
and another nipple to make it work, but I now have a decent ball valve instead of the piece of crap that came with it. Parts
cost me about $100 a side. It's tucked up against the engine
under the starter so its really protected from impacts.