The B44 steering blocks won't fit on the BJ4's aluminium caster blocks, to use them you need the 9720 caster blocks, 9647 bushings and 4-40x7/16" screws, the whole assembly then fits onto the arm as normal. I believe the bearing crush washer is different too so you might need that as well (9751)
The BJ4's standard steering blocks are from the XX/XXX4
