Differences in front suspension, 69½ used smaller spindle/bearing size common to all '69s. The 250 engine was added approx a month into true '70 model production. V8 option added early in '71 model year. Mustang had something like 15-18 differences(no I don't know them all, I'm primarily a drive train guy). Most glaring was '64½ had generator, 170 6cyl and 260 as first V8 option, plus a regular fuel, 4bbl 289 used '64 five bolt pattern block to bell housings. True '65 got alternator, 200 6cy, with 2bbl 289 as first v8 engine option and 4bbl premium fuel 289 as second. Fastbacks were introduced with true '65 as well. I remember something about non-adjustable passenger seat in early models.
