The BJ4 one won't fit out of the bag because the front shaft is too long due to the BJ4 not having the longer slipper assembly.
I haven't seen any ready-made one for the B44.
The hookup into the transmission should fit so all you'd have to do is find a fitting bone to fit the front and middle drive cups. Maybe you could even redrill and shorten the BJ4 one.
Good luck
