You turn the outside of the bell
My understanding is you take a /5LWB or /6 drive shaft and bell coupling and turn the outside of the coupling(F.D. end)down so it fits inside the /2 swing arm housing. Don when you turned down the taper to fit the /2 coupling you actually shortened the drive shaft and the /2 coupling made it even shorter. I just gave a friend a complete /6 drive shaft for his conversion and that is what we found and what he did to make it work without the adapter stuff. You gotta post a picture soon!!!