Bottom brackets were pretty confusing to me at first, and FSA makes so many and have so many adapters it further confused the issue. I think you are doing what I did... I have a 386EVO crankset, which utilizes their MegaEvo bottom bracket to fit standard BSA threaded shell.

I've not actually finished the build yet so have not had it on road but seems to be very nice setup. Many folks say you can't put 30mm spindle in the old BSA bikes but this allows you to do just that!