Donsz - your conclusion was incorrect, there's nothing ambiguous about the assembly manual, it shows exactly how the factory did it for the 55-57's, the identical core support was moved back to other mount points on the inner fenders [there's triangular reinforcers there], and sheet metal shrouding was added
in front of the rad top and bottom, as seen on
this original 57 ... I have a '57 panel 'in progress' that's a factory V8, one day I'll have some good pics of it being reassembled
Bill