"M" in a Monaco?
NO! Production of M-series'63s ceased shortly after the beginning of January '63, while Monaco production began around mid-January '63 on through end of '63 production. Sales literature during the period the Monaco was offered did not even mention the M-series engine.
Why no "M" in the Monaco? Too many complaints from owners of engine fires, poor mileage, hard to keep in tune, etc. With the upscale sedate, hard-to-please clientel Ford was aiming the Monaco at, the last thing they would want to do is have a lot of irate owners, warranty work, etc.