They may have been sold as 1965 Mustangs, but there were a few differences from the April 1964 versions and the actual 1965 models sold later that fall.
The 64.5 cars had a slightly different hood with a sharper front edge, this was why there was a C4 part number on the headlight bezel to match. The '65 hood was rounder and had a different bezel.
Other changes were a slightly different gas cap, several paint colours available on the first 64.5 models only, the first ones had a generator while an alternator came into use for the 1965 models, meaning that the dashboard said "GEN" vs. "ALT" and there were other minor interior trim differences.
Engines were different as well; a guy at work was rebuilding a 1964.5 version (back in 1978) and found it had a 260 engine, the base V8 in 1965 was a 289. The base six was larger in 1965 as well. Only the 271 hp. 289 was shared between the two versions.
The "C4ZZ" numbers weren't part numbers but were engineering numbers, they referred to the year of the design, not the car model year. So if a certain part was used for two model years, it likely retained the original number. Example, C4ZB-13449 was the number for the tail light bezel, but the same design was used from 1964-1966 so the number remained the same.
Wayne, while I'm thinking about it, why is it that I can't use the emojis on the top bar on my phone, but I can on my PC ?
)
