Yeah, I screwed up on this one. It actually is a Mercury, after all. I thought the letters on the hood were possibly "CH", as in Monarch. Also thought "Montclair" sounded too "Frenchy" to be a U.S. series. The dual headlights could be '57 or '58, depending on where they were sold. Some states still did not allow dual headlights in 1957, but this was cleared up by 1958. I have seen some 1957 Chryslers and DeSotos the same way. Some have single headlights, while others have duals. Further research turned up that Ford of Canada did not actually produce any 1958 Monarchs. That spot on the sales ladder was replaced by the new, hyped Edsel. Once it was realized that the Edsel was going to be a huge flop, the Monarch was re-introduced for 1959 and 1960. I am sorry for the misinformation.
Dave