Interesting article... My car is one of those early models and it certainly has the differences. A May 1964 model.
I guess I had better stop calling it a 1964-1/2 🙂

Last edited by Toploader (2/23/2023 2:32 PM)

My convertible has a 6/17/64  build date and it had a generator.

According to Colin Date, Original Mustang, the last official 64.5 left the Dearborn or San Jose plant on July 31, 1964.  Total 64.5 production was 121,583.

Rufus68 wrote:

Regarding Toploader's car, what engine code is in your VIN? 

Mine is a D Code. It came with a 289, 4V, 4 speed and generator. It was built in May of 1964.

I would bet that the changes were phased in.  If the cars were built at different plants on the same day they might have different equipment based on what that plant still had in stock.  Case in point, there were changes made to the 6.0 Diesel engines in mid 2005, called commonization.  My truck, despite being a '06 with a build date after the changes supposedly were in effect still had 18mm cylinder head dowels (later engines had 20mm dowels) and the small injector hold downs (T40 instead of T45), but had 4 upper head bolts (earlier had 2).  Its somewhere in the middle of commonization.  I've owned the truck since it was new, but ordered head gaskets based on the VIN and ended up with the wrong ones. 

Ron, before July 1965.

My 65 has a July 17, 1965 build date, “245577” sequence number.

It came with Pony interior, air conditioning and center console, power steering, 4 wheel power drum brakes, 289/C4 green dot/8” with 2.80 open differential.

It has both 65 and 66 parts on it.

65…

Original heater blower motor had a Jul 23 1965 stamp on it.

Pony door panels had April 6 1965 and February 19 1965 with “C5” engineering numbers.

Air conditioner …has driver side connections and faceplate/vents (66 are in center and different faceplate/vents).

5 gauge instrument panel (ammeter is inductive not 2 post connection “C5”).

Transmission kick down is bell crank 65 style for c4 transmission (66 has a cable).

65 emissions (PCV only, no air pump).

Early 65 style engine brackets and motor mounts


66…

2 barrel intake has “C6” engineering number casting.

289 heads have “C6” engineering numbers  (air injection ports not drilled out).

Emergency brake cables, long one piece with horseshoe equalizer (65 had two short cables).

66 style cowl and wiper arms (65 bolted on, 66 has splines).

My 65 Fastback is a November 64 build date from the Dearborn plant
No rear seat belts (or the provisions for them)
No back-up lights
Clip-on window cranks
End clips on the wraparound Fastback trim
No dimples for dual exhaust system in floorboard under rear seat
Two-speed heater blower motor (not sure when they went to the 3-speed motor)
 
As I understand from people that worked in the local GM plant years ago; workers would pick parts from a parts bin next to the assembly line for the various assembly of the car, they would simply reach into the bin and grab the part needed.  When the bin go low in parts, someone would simply add more from the storage area.  So, new parts could be placed on top of the older parts, and if/when the bin got down to these older parts, they would be installed on the car regardless.  There just wasn’t any control on many parts as there were considered equivalent.  This is why some newer models have parts that should have been phased out months, or year, earlier. 
I understand these details get very sticky in a concours restoration where the car was re-assembled with the original parts found the car, but the judges say that it isn’t correct.

MS wrote:

My 64 convertible has August 1964 build date but has an alternator. Wonder what the cutoff date was. ?

The Dearborn and San Jose factories closed for 2 weeks some time in late July or early August for the year model changeover but they were not closed for the same 2 week period. When the factories restarted after the 2 week break ALL cars received the alternator. In other words there was no phase in period as generators were used up and alternators replaced them, the change occurred the day production resumed. Likewise the engine options and the change from 5 bolt to 6 bolt 289s occurred on the first day of resumed production.
 

As someone who worked in three different auto plants albeit another maunfactuerer and in the 80s and 90s, I can also tell you cars did not always run down the line in sequential numbered order.  Cars were pulled off the line to repair major defects that could not be fixed as the line was moving, and I spent most of my time in body in white, cars were pulled off to check spot weld integrity, which took time.  Basically that consisted of using a hammer and flat chisel between panels to make sure welds held up.  In my time, this was government mandated, and recorded, I can't speak to if that was done in the 60s, but seems likely.   The same  an be said for major paint defect repairs, and so on and so forth down the line till the end.  That could possibly affect running changes as to which parts got put on a car and so called "oddities" talked about over the years. 

And yes assembly lines were shut down for one to two week periods for model changeovers.  That is when a lot of the equipment maintenance work was scheduled.  There was only so much you could get done on a two day weekend.   We used to have to save some vacation days for the time off if we wanted to be paid.   Lines used to also shut down for the week between Christmas and new years, again, that maintenance thing.   Running changes usually were implemented during these times. 

Yes, sometimes old parts were just flat out taken away and scrapped or turned into service parts, and sometimes parts were just integrated into existing stock.

Texas! wrote:

TKOPerformance wrote:

Texas! wrote:

The Dearborn and San Jose factories closed for 2 weeks some time in late July or early August for the year model changeover but they were not closed for the same 2 week period. When the factories restarted after the 2 week break ALL cars received the alternator. In other words there was no phase in period as generators were used up and alternators replaced them, the change occurred the day production resumed. Likewise the engine options and the change from 5 bolt to 6 bolt 289s occurred on the first day of resumed production.
 

Playing devil's advocate I wonder if that's actually what happened or what Ford has said happened.  Assembly lines don't stop.  If a shipment of engines, or alternators was late, even by an hour and yet there were old style engines or generators sitting that weren't supposed to be used, but hadn't been picked up yet, well, I would suppose they kept the line moving.  I've seen aberrations in vehicles made in the 2000s.  It wouldn't shock me in the least if it happened in the '60s. 
 

The alternator equipped cars required a different wiring harness and instrument cluster than the generator cars. Do you think somebody was going to run down those parts to go with a generator so they could keep the line moving?
The 5 bolt 289 requires a different bellhousing, block plate and transmission than the 6 bolt 289. Do you think somebody was going to chase down those parts to go with a 5 bolt 289 so they could keep the line running?
Have you ever seen anybody claim they have a post August 1964 Mustang with a generator or a 5 bolt 289?
I'm saying it didn't happen. Ford had the assembly plants stocked with sufficient alternators and 6 bolt 289s when production of the so called '65 Mustang began in August 1964.
 

First, I'm not saying anything did or didn't happen. 

Second, I'm aware of the differences between the two versions of the car.  The engine/trans and associated parts don't seem much of an issue as that entire subassembly was put in the car as a unit.  The wiring harness, cluster, etc. for the generator vs. alternator to me is more compelling, but it begs the question were any cars built with a 5 bolt 289 and an alternator?  Again, not saying it happened, but also not saying it didn't or couldn't have. 

Third, no, I've never personally seen or heard of one, but an absence of proof is not a proof of absence.  The only way to prove it beyond all doubt would be to have the records of all the cars built in 1965, but my understanding is that those records no longer exist.  As an example, for decades it has been speculated that there were Mustangs built with the 427 factory installed.  No one has yet been able to prove they have one, but debate about what may or may not have been listed on an options sheet for new car buyers, and what may or may not have been built or sold continue to rage. 

The whole point of this is that we often take things in the automotive world as absolutes which turn out not to be absolutes.  When I see vehicles built with equipment different than a VIN would suggest in 2005, with all the systems they have in place today to ensure accuracy; it leads me to wonder what could have happened in 1964 when they were relying on pieces of paper.  For what that's worth, I once found the build sheet in a car I was working on that turned out to be for a different car.  Same year, model, etc., but the options were different and the VIN didn't match.  Strange things happen on the line sometimes. 
 

TKO & BB – your comments fall in line with discussions with people I know that worked in the local GM factory and some people I know that worked at Ford’s Dearborn plant. 
One guy told me that while it didn’t happen frequently, some cars being driven onto the transport trucks missed the ramps and either crashed into the truck, or rolled over.  A fork lift came out and hauling them back into the factory where who knows what happened to them.  (This was before drug and alcohol testing had started!) 

Stories, I guess there are a lot of them.  Here’s another one; at the start of friend’s day shift his boss was looking at a trailer filled with new cars that were to be shipped that day and noticed a driveshaft laying on the ground.  They went over to investigate, the automatic transmission on one of the lower cars on the trailer was stolen overnight.  The boss was quite angry and was asked what he would do if they got the person, he replied “I’d hire him, any one who get that out is someone I want working for us”.