I have a friend who is restoring a 57 Saratoga---he is using a 392 and is looking for a 58 dual 4 set-up should anyone have one for sale--also I have a dual 4 manifold with the 56 casting #---it is exactly like any B manifold except the 3 ports which are closed on all manifolds that I have seen---to prevent water from entering exhaust manifolds are open on this manifold----I had to plug the holes in order to use it on this B I am working on---does anyone know what this manifold would have been used on ?---Johnnie Slayton