Ask scorch, but I think you need an Italian threaded BB. Shimano do the ubiquitous BB-UN54 in Italian if it's for a budget build, and Campag do Record Pista in Italian if you want something flash.
Oh, and it's ХВЗ, not XB3, miss.ua would kick me if I didn't point that out.
so do you think i should stick to threaded?