Drivetrain Tags

[66TotalPerf]

I'm helping my dad with his '66 (6s1097) and have a few questions regarding drivetrain tags. His Ford VIN estimates it ran through SJ in Feb '66.

For the T10M, my understanding is it didn't come with an ID tag of any kind, just the date codes cast into the main/tail housings?

For the rear end, I believe GT350s came with a Ford tag but with a unique stamping due to the ratio/locker options unique to GT350s? Should his car have a tag with the following format for a 3.89 open diff?

DSO      C6ZX-C         (FoMoCo within an oval)
3.89      XXX (DATE)      925 (3:89 BUILD CODE)

Thanks!
Brent

[J_Speegle]

I'm helping my dad with his '66 (6s1097) and have a few questions regarding drivetrain tags. His Ford VIN estimates it ran through SJ in Feb '66.

For the T10M, my understanding is it didn't come with an ID tag of any kind, just the date codes cast into the main/tail housings?

Guess you have found steel metal that made up the unibody with Feb stamping dates? IF so maybe it was completed at San Jose early March? If your using something else as a guide then that guess would need to be possibly adjusted.

As far as any external transmission dates, yes the casting dates you mention are the only guides I know of on the transmission your mentioned

For the rear end, I believe GT350s came with a Ford tag but with a unique stamping due to the ratio/locker options unique to GT350s? Should his car have a tag with the following format for a 3.89 open diff?

DSO      C6ZX-C         (FoMoCo within an oval)
3.89      XXX (DATE)      925 (3:89 BUILD CODE)

Yes an open 3.89 would have those stampings on the tag. A "locking" one would be different and the Ford oval is often very weakly stamped in comparison to everything else.

Here are examples of locking (top) and open (bottom) tags that were assembled in Feb 1966.

For comparison (dating of parts) the upper example, completed at Sterling plant the last week of Feb) ended up in a car with unibody sheet metal dates (limited number of examples)  from Jan 1966.



Hope this helps

[Bob Gaines]

Shelby American inialy installed the Detroit lockers in the 65 GT350's. Later in production SA was able to have Ford do the installtion saving production costs. SA internal memos indicate that for 1966 production individual Dealers would see to Detroit locker or Traction Loc installations instead of ether SA or Ford. The C5ZX tag pictured is a example of a Ford installed 3.89 Detroit locker in a 65 GT350. The C6ZX is a example of a open 3.89 in a 66 GT350.

[66TotalPerf]

For the build date, I used this chart (ignore the green) and since his Ford VIN sequence portion is 164xxx, it says those cars went through SJ in Feb '66? Plus the cast engine block date code starts with 6Axx which I believe corresponds to Jan '66? We haven't crawled around inventorying sheet metal date codes yet, but are going to over Thanksgiving break to confirm all are dated sometime between Nov '65 and Jan '66?

For the C6ZX-A/B/C portion, what's the significance of the last letter (A/B/C)?

For the rearend tag date code, assuming we also want to find a tag dated Nov '65 (5L?) to Jan '66 (6A?)?

Thanks!

[J_Speegle]

For the build date, I used this chart (ignore the green) and since his Ford VIN sequence portion is 164xxx, it says those cars went through SJ in Feb '66? Plus the cast engine block date code starts with 6Axx which I believe corresponds to Jan '66?

Well the chart like you posted is only a generalization and we know for later cars where were have more data this sort of things can be off by 4-5 months and in unusual cases much much more. Best you can get IMHO is a basic guess based on the facts you can collect and document then try and finger in transport time and even compare (in your example) possibly 67 date spreads. Never going to be exact.

We haven't crawled around inventorying sheet metal date codes yet, but are going to over Thanksgiving break to confirm all are dated sometime between Nov '65 and Jan '66?

Will look forward to hearing/seeing the date collected. Remember that the dates and which exact panels they go to is important. When laid out will allot of other data you can almost or sometimes account for each shipment of panels to the assembly line to be used on a group of cars especially on panels that for example were only used on Certain body styles.

For the C6ZX-A/B/C portion, what's the significance of the last letter (A/B/C)?

For lack of better terms at the moment, they identify a different version or model of the original -A part

For the rearend tag date code, assuming we also want to find a tag dated Nov '65 (5L?) to Jan '66 (6A?)?

Would not go that far yet but one with those dates (maybe Dec - Jan) most people would not take notice of it. Not to say that those dates would line up with other cars possibly built at the same time.

[66TotalPerf]

We'll get those dates and go from there.
Thanks!

[6s1640]

The chart shown in reply No.3, looks a lot like one that I may have posted in a prior thread with my red and green markings.  I believe the chart is a summary of a Ford document to forecasting production rates.  This chart could have been used by suppliers for forecasting parts needed for a given month.  This is very similar to a chart a major airplane manufacture used for forecasting airplane builds and incorporating changes.  This was a tool.  It is not intended to be an exact predictor of build dates, but should be used with other information extracted from the car in question.

For example, I have an original engine is stamped with a 10-24-65 assemble date, but this tool shows the estimated San Jose build date on 10-15-65, before the engine was even assembled.  This obviously does note work.  The fenders are dated August of 1965, but I find other date stamping in October 1965.  So it is likely the car has a San Jose build date in the first or possible the second week of November 1965.

There is the HiPo Registry that has actual door date dates that can be used to estimate a specific cars San Jose build date.  It is the combination of information used to estimate the original build date.  These dates should also be bounced against the dates in the 66 GT350 Registry to see if they make scene and track.

I hope that helps.

Cory

[J_Speegle]

............. These dates should also be bounced against the dates in the 66 GT350 Registry to see if they make scene and track.

Unfortunately we don't have solid info in the 66 registry for arrival dates for example or many other dates as we do for the other years but yes good to compare to what dates may be available and evaluate from there.

Using projected or scheduled dates is a hit or miss situation but can be included in the possibilities. Examples of the possible spread between these and real completion dates can be seen in the 67 data we do have available

[6s1640]

Hi Jeff,

I must not have been clear on my post.  When I referred to the 1966 GT350 Registry, there are dates to bound the right side of the time line.  They are:

1) Shipping date from SAI
2) Radio installation date at Hi Performance motors
3) Warranty dates

Less important are:

4) Order Dates (Which has no bearing on any production date information.)

The dates for 1-3 better be to the right of any estimated San Jose dates.  This is a check on the possibility of the San Jose date.

If the San Jose date is two weeks prior to SAI shipping the car, it is likely the San Jose date is incorrect.

But if the estimated San Jose date is two months prior to the SAI shipping date, then the build date is "plausible."  Time is needed to:

1) Hold and transport engine from build site (At a minimum 3 days, could be a week or more.)
2) Hold and transportation from San Jose to SAI,  (Could be a couple of days to a week.)
3) Hold time at SAI plus build time and hold time waiting for shipment.  (Could be few weeks to a couple of months.)

At best is seam the shortest time from the estimated San Jose build to ship date could be as short as a month if everything is working smoothly.  The longest could be a few months as well.  We will never know that actual flow time for each car, but is stands to reason, the estimated San Jose build date better have enough flow time for all of the above actions 1-3 to occur.

I also checked the "The 289 High Performance Mustang" registry (3rd edition, page 108) door tag data  and found, by varying the assumptions, the door tag scheduled build dates where within one day of the Production Forecasts (Chart above), or even on the same date.  This suggests that the two independent sources validate each other.

A third piece of information I have on the car in question, is from the Summer 2023 "Shelby American" magazine, page 64, an article on the rear seat package tray by Steven Sloan, on a letter dated November 8, 1965.  This letter shows there were 100 white four speed cars with four seat ordered from the San Jose plant, October 1965.  My car was in that block of cars, further supporting the estimated build date in October. 

So I am pretty confident my car was built late October 1965 to very early November 1965.   I have three sources that support this estimated date, plus the SAI dates that support a time line for the estimated build date.

I hope that better explains my claim.

Cory

[J_Speegle]

First thanks (from me) for a second try at trying to explain your understanding and opinions.

A few specific comments or sections of your reply

From your earlier post.

For example, I have an original engine is stamped with a 10-24-65 assemble date, but this tool shows the estimated San Jose build date on 10-15-65, before the engine was even assembled.  This obviously does note work.  The fenders are dated August of 1965, but I find other date stamping in October 1965.  So it is likely the car has a San Jose build date in the first or possible the second week of November 1965.

Do you have any of the dates from what made up the unibody for comparison. Bolt on parts can be so unreliable for obvious reasons? Easiest ones with an assembled car are inner fender panels in the engine compartment,sway bar brackets, rocker panels, dash (on the bottom edge often near the center) and main floor under the rear seat cushion are on passenger side. Rather than ranges (statements like "my dates are all from April") isn't as helpful as specific dates for each specific part. With exact dates and panels we can place those within a period of the same parts identified on other cars and when that shipment of parts was at San Jose. Graphed out these patterns become self evident.

1) Hold and transport engine from build site (At a minimum 3 days, could be a week or more.)
2) Hold and transportation from San Jose to SAI,  (Could be a couple of days to a week.)
3) Hold time at SAI plus build time and hold time waiting for shipment.  (Could be few weeks to a couple of months.)

At best is seam the shortest time from the estimated San Jose build to ship date could be as short as a month if everything is working smoothly.  The longest could be a few months as well.  We will never know that actual flow time for each car, but is stands to reason, the estimated San Jose build date better have enough flow time for all of the above actions 1-3 to occur.

Best comparison IMHO and a look into spreads, delays and dates is the 67 production period since we have real completion dates and scheduled dates to compare. This also provides (since it is at the same plant only a year later) an insight into spreads between things like engine cast and assembly dates and car completion dates. Think looking at those spreads giver a much more solid feel that some of the other methods some use at hopefully guessing when the car was completed in 66 or even 65

I also checked the "The 289 High Performance Mustang" registry (3rd edition, page 108) door tag data  and found, by varying the assumptions, the door tag scheduled build dates where within one day of the Production Forecasts, or even on the same date.  This suggests that the two independent sources validate each other.

Going to disagree on this point. Since I believe these two quoted resources are based on information from the same original source they don't validate one another but match because they came from the same sources. The workers at San Jose when entering an order and assigning groups of VIN's and scheduled or projected build dates were given start VIN (sequential numbers) to attach to the order and a date from what you have and others have labeled "production forecast".

A third piece of information I have on the car in question, is from the Summer 2023 "Shelby American" magazine, page 64, an article on the rear seat package tray by Steven Sloan, on a letter dated November 8, 1965.  This letter shows there were 100 white four speed cars with four seat ordered from the San Jose plant, October 1965.  My car was in that block of cars, further supporting the estimated build date in October. 

Since there are a number of dates on each DSO  (Add/Delete) form it might be easier to clarify which DSO order your referring to. Also there are orders for other 66's (automatics for example) that are dated earlier than the group you mention above.

[6s1640]

Hi Jeff,

Good discussion.  Here are my thoughts from your comments:

1) Do you have any of the dates from what made up the unibody for comparison?    Yes, one of the latest dates I can find is on the drivers side forward inner panel.  It is dated 10-15-65.  This date supports a late October build.  Any person trying to narrow the build date to their car must consider these body panel, unibody dates codes.  I agree.

2)  Best comparison IMHO and a look into spreads, delays and dates is the 67 production period.  Agree, do you have data you can share these production flows, etc.?

3)  Going to disagree on this point. Since I believe these two quoted resources are based on information from the same original source. I don't disagree with you, because they produce nealy identical results, they are likely from the same source.  That is a good thing, that they match.

4) Since there are a number of dates on each DSO  (Add/Delete) form it might be easier to clarify which DSO order your referring to?  I do not have the exact DSO number, but I expect Howard Pardee or Steven Loan should have.

In conclusion, I can't quite tell if you are saying the Production Forecast Chart (attached above.)  and/or door tags are not valid sources to help estimate the San Jose build dates.    From my experience they are very useful, especially when combined with other information, such as body panel dates, engine assembly dates and DSO documents.  I am pretty convince my car, 6S407 was built in late October or even very early November 1965.  And since today is November 1, I am confident I can say my car was built 58 years ago, give or take a few days.

Take care

Cory

[J_Speegle]

Guess I should state that I'm not disagreeing with your estimate as to when 6S407 was completed at San Jose just discussing how you arrived there and some other things to consider that I may be able to offer you and others watching this thread

From your reply #8

A third piece of information I have on the car in question, is from the Summer 2023 "Shelby American" magazine, page 64, an article on the rear seat package tray by Steven Sloan, on a letter dated November 8, 1965. This letter shows there were 100 white four speed cars with four seat ordered from the San Jose plant, October 1965.  My car was in that block of cars, further supporting the estimated build date in October.

When an order or letter was typed, submitted or received would only place a date that the car, if part of that order, would not likely be built before but does not limit how much later than that date it could have been built. Believe that order that the letter referred to was constructed earlier than the letter mentioned. Need to reread Steve's article to see what else I can glean from it when I can find time.   So IMHO that for me does not support the idea of your car being built in October just supports that if would not have been been built the specific date that letter identified.

1) Do you have any of the dates from what made up the unibody for comparison?    Yes, one of the latest dates I can find is on the drivers side forward inner panel.  It is dated 10-15-65.  This date supports a late October build.  Any person trying to narrow the build date to their car must consider these body panel, unibody dates codes.  I agree.

Thanks though I wish there were more examples

You mentioned earlier that your fenders were dated for "August of 1965"  Would those happen to be 8 6 D2 date for the drivers side and something like 8 11 or 12 on the passenger?

Have records of other cars with the same drivers side forward inner panel and date (likely same shipment) to complete the stamping is it 10 15 D2 with the 2 being inserted upside down in the retainer?

Do also have examples of the same panel with dates of 10 16 being installed as late as mid November projected build dates at that plant

2)  Best comparison IMHO and a look into spreads, delays and dates is the 67 production period.  Agree, do you have data you can share these production flows, etc.?[/quote]

Would need would need to be calculated and arranged to make sense.