It's best if you get somthing like a ooga horn from like speedway or Harbor freight, your other option is any horn from any 70's or 80's, or any car b4 1990 or so, just has to be 12 volt which, from like '65 on up was, 6 volt really got inferior in '55 and most cars after that were but there were still a few 6 volters but like a 60's Bel air or 70's Impala should have a horn that would sound close ur '57's original but most any American 12 volt horn will work.