I have two fuel filters and am trying to figure out which one is correct for my '58. I have a very late '58 so I know the correct fuel filter is the flat top verses the dome. One has the AC on top and the other has the AC on the fuel inlet/outlet like the later ones. The one that has the AC on the top is marked with a 57 on the inside so it appears to have been made sometime in '57. I can't make out the number on the inside of the other one so I can't tell when it was made. Neither of them have the "depression" in the center top like the later ones do. Thanks, Ted