The designation's so widespread, it's almost become gospel among Mustang enthusiasts and the collector car world in general. You'll see 1964-1/2 as a model year in the titles of Mustang books, in prior Hemmings articles (nostra culpa), even on Ford's own website. Except, officially, Ford never designated any Mustang as a 1964-1/2 model year car.

"All of the first production Mustangs built from February 10, 1964, through July 31, 1964, were titled as 1965 model year cars," according to Robert Fria, an expert in pre-production and early production Mustangs who wrote the definitive book on the subject, "Mustang Genesis: The Creation of the Pony Car." As Fria and many others have pointed out, just looking at the VIN of any early production Mustang should bear that out: All of them - whether the one Fria discovered with serial number 100002 or the one that Captain Stanley Tucker bought with serial number 100001 - start with the digit 5 for the 1965 model year.

Case closed, really short article, right? So then why did the 1964-1/2 "model year" become so widespread to the point where it gets its own entry in year-by-year Mustang reference books and where the Mustang Club of America reportedly considers 1964-1/2 as a separate model year?

Part of it comes down to the introduction of the Mustang in April 1964, well out of line with the traditional model year cycle: The rest of the 1965 Fords didn't debut until that September. While unusual in comparison with prevailing trends through the rest of the industry, it was actually in line with Ford's mid-year introductions of the Falcon Futura and Galaxy 500XL Sports Hardtop the year prior, as Brad Bowling pointed out in the "Standard Catalog of Mustang" (which, incidentally, has an entire section on the "1964-1/2" Mustang). Indeed, given the success of such introductions - the Mustang essentially had the field to itself when it came to new-car publicity that spring, and that introduction date may have even been key to the avalanche of first-year sales - one has to wonder why we haven't seen many subsequent mid-year introductions. (Outside of unintentional ones like the 1970-1/2 Camaro, its introduction delayed by a strike.)

Read on for more...