the jap stuff is based on shrunken vintage guards so.... you will have alot of problems.
you would probly be better off selling the u.s. and buying a jap guard, the u.s. stuff sells for higher than the jap and you would basically be garenteeing yourself a good fit and you may have a few dollars left over to put in your pocket, as opposed to permanently modifying a u.s. guard. altho im not even sure if you can mod it to fit properly.
