Topic: 1966 Low Profile 8K Rally Pac - tachometer differences

[Morsel]

Hey all,

I wanted to ask the question because it really didn't get answered on the previous thread. Does anyone know the difference between the two original rally pacs, was one a dealer add on and one an assembly line version, or was there change over at some point, or a plant difference? Look at the attached two photos, looking specifically at the tachometer, notice one has the RPMs listed every 1000, and the other has it listed every 500... The one that is every 1000 is one Jeff just posted, and the other was just an example I found online of what I'm talking about, but matches my original one.

I looked around and can't find any info on this difference, I've seen both examples on cars.

Thanks,

Jason

[outlawincorporated]

JASON.

images from two of my unrestored 66 cars. one is a K code the other is a GT.  both cars have the original rally pacs and both have different tachs

just so we are all on the same page the K code was a NJ car with a build date in march 1966 and the GT was a SJ car with a January 66 build.

I also have a NOS 66 6000 rpm rally pac that also is the 500 rpm tach.

guess it could be either style and maybe it could come down to assembly plant or build time different???
the plot thickens


regards.

PHILL BERESFORD
MELBOURNE.
AUSTRALIA.

[Morsel]

Thanks Phill, that pretty much answer my question for the most part... I knew there were different suppliers for the Rally Pacs, I just wondered if it was a grab bag or if certain plants used a certain one at a certain time, or if say early 66 as you show has a RPM increment of 500 and the later 66 had increments of every 1000. But I'm not going to worry about it too much, sounds like I'm ok with what I got.

Thanks,

Jason

[196667Bob]

Jason : Don't jump too fast. I've done a lot of research on these the last week or so, but it will be a day or so before I can put everything together for a somewhat coherent Post.

Bob

[Morsel]

Jason : Don't jump too fast. I've done a lot of research on these the last week or so, but it will be a day or so before I can put everything together for a somewhat coherent Post.

Bob

Ooh, OK, I'll be curious what you have to share.

Thanks Bob...

[196667Bob]

1964-1/2 to 1966 RALLY PACS - A HISTORY - PART I

(READ BEFORE PART II)

Over the past several weeks, I have done a lot of research on Rally Pac's, not just for this thread, but prompted by it to find more information about mine also.
I have used a lot of resources, and come up with a lot of information. The hardest thing is how to present it all so that it will make sense, be informative, and be documented. The method I have decided upon is to present it first from a potential owner's standpoint from 1964-1/2, 1965 and 1966 model years, then from an owner's point during that same period, and finally from the Ford Dealer's Parts Department.

In the following narrative, both Parts I and II, available Service Part Numbers and Engineering numbers are used for identification purposes.

POTENTIAL OWNER

The first thing as potential owner might look at "back then" would be the Sales Brochure.

1964-1/2 - The 1964-1/2 Mustang Brochure dated 2/64, both lists and shows a picture of the Rally Pac Option ( picture #1). The Rally Pac shown is the "high-profile" type (or as I like to call it the "visor" type). There is no mention of 6 or 8 cylinder application, nor of rpm's for the tach.

1965 - The 1965 Mustang Sales Brochure, dated 8/64,  again lists the Rally Pac as an Option, and shows the high-profile type with no mention of 6 or 8 cylinder application nor of rpm's (picture #2)..
   A Mustang Sales Brochure dated 4/65 was subsequently printed  mainly to introduce the new Mustang GT, and the new "Interior Decor" Options. Both of these Options included the new Instrument Cluster with gauges replacing the standard "idiot lights". Ford recognized that if either of these Options were ordered with the current Rally Pac, the gauges would be somewhat obscured. To solve this potential problem, Ford added the "low-profile" Rally Pac (commonly, and mistakenly, called the "1966 style" Rally Pac). This brochure shows only the low profile Rally Pac, along with the new "gauge type" Instrument Cluster; yet the high-profile type was still available for the "Standard" Instrument Clusters. Once again, no mention is made of 6 or 8 cylinder application, nor of available rpm's. Looking at picture #3 from this brochure, one can see that the Rally Pac shown is of the 8000 rpm variety, and is numbered every 500 rpm.

1966 - The 1966 Mustang brochure, dated 8/65, shows the low-profile Rally Pac, which would have been used on all 1966's, since all 1966 Mustangs now had the "full gauge" Instrument Cluster. As in the previous brochures, no mention is made of engine application or rpm's. The picture in the brochure once again shows an 8000 rpm tach, numbered every 500 rpm (picture # 4)

The next thing a potential buyer might do is go to his local showroom and talk with a Salesman. Once a prospective buyer had selected a car (in this case a Mustang), and of course sometimes before a selection had been made, the Salesman would probably have shown the buyer the section about the particulars of that car contained in the Product Facts Book. These were typically 3-ring binders that had sections for each model car, with details on suspension, steering, engines, etc. that were specific to each model. Contained in each section was a page or two of "Options and Accessories" available for each model. These "model specific" sections are what has been reproduced for many years  and titled "illustrated Facts" or "Illustrated Facts and Specifications" Manuals. These were not put together by someone who compiled all of this information for us hobbyists, but taken right from the Ford Facts Books.
I have attached a copy (picture # 5) of a page from the Ford 1965 Facts Book (1966 is similar) showing the Options and Accessories available for Mustangs.

Before proceeding, a little aside in regard to "nomenclature". Unfortunately, in most of the publications in the 60's, Ford used the word "Option" to mean both Factory Options and Dealer installed Accessories. In the "Facts Book", they note in the title "Mustang Options and Accessories", but before the listing, they note that "items" installed at the Factory are designated as "F", and those by the Dealer are designated by "D". In fact, all of the items noted as "D", are actually Accessories (could be purchased at the Ford Parts Department). If these Accessories were either purchased at the time of placing the car order, or after the Dealer received the car and the Owner purchased them and had the Dealer install them, they were designated as "Dealer Options". In order to avoid confusion, I have always differentiated these as "Options", meaning Factory ordered and installed Options ; Accessories, meaning items which could be purchased at the Ford Parts Department ; and Dealer Options as Accessories installed by the Dealer.

Getting back to the subject at hand, note on the sheet from the Facts Book, that the Rally Pac is shown both as a Factory Option and an Accessory/ Dealer Option. The Salesman would then check his 1965 Model Pocket Price Guide (picture #6) and note to the customer that the Rally Pac was available from the Factory for $70.80 (as we will see later, this same item as an Accessory was $75.95, and that did not include installation).

For 1966 models, the 1966 Model Pocket Price Guide (picture #7) shows the Rally Pac at $69.30.

CURRENT (in 1964,65 or 66) OWNER

For the person who already owned a Mustang, and was looking to add an Accessory to it (in this case a Rally Pac), they would go to the Ford Accessory Catalog (since the 1964 Accessory Catalog was printed well before the "1964-1/2 Mustang" was introduced,  I will start with the one from 1965).

1965 - This "brochure/catalog" only contains a copyright date of 1964, no specific month (although these were usually available at "Model Introduction" time). After sections on "normal" Accessories available for 1965, there are sections titled "Cobra High Performance Kits" and "Parts and Accessories with GO for the high performance enthusiast". In the latter section, there are two different "high profile" Rally Pac's shown (picture #8) ; C5ZZ-10B960-B (6 cyl), and C5ZZ-10B960-C (8 cyl), each listed at $75.95.

1966 - The 1966 Accessory catalog became more of a catalog than a brochure. Once again, no exact date was noted, only "Copyright 1965". Interestingly, the Rally Pac does not appear in the 1966 Accessory Catalog. However, in 1965, For began printing a "Ford High Performance Catalog", and a 1966 version was also printed. These were also sources for available parts, and a current owner might have gone to these, especially in 1966. In order to keep the "complete picture", we'll look at both 1965 and 1966 versions.

1965 - The 1965 Ford High Performance Catalog is dated 2/1/65. Page 40 is titled "Other High Performance Equipment" and shows the Rally Pacs (picture #9). The two "high profile" ones shown have the identical Part Numbers and notations shown as in the 1965 Accessory Catalog ' C5ZZ-10B960-B, and C5ZZ-10B960-C, and each at the same $75.95 price.

1966 - The 1966 Ford High Performance Catalog is only dated "Copyright 1966". The Rally Pacs are found on page 28 (picture #10). Note that now, the C5ZZ-10B960-B no longer is listed, and two new Part Numbers are shown. Specifically noted is that 6000 rpm Rally Pacs are for 6 cylinder models, and 8000 rpm Rally Pacs are for 8 cylinder models.  Applications and Part Numbers are listed as follows :
   
   1965 Mustang(except GT), 8 cyl w/ indicator lights.................C5ZZ-10B960-C
   1965-66 Mustang (before 2/1/66), 8 cyl with indicator lights....C5ZZ-10B960-D
   1966 Mustang (from 2/1/66), 6 cyl with indicator gauges.........C5ZZ-10B960-G
   1966 Mustang (from 2/1/66), 8 cyl with indicator gauges.........C5ZZ-10B960-F

All are listed at $74.10 each.

CONTINUE WITH 1964-1/2 to 1966 RALLY PACS - A HISTORY - PART II

[196667Bob]

1964-1/2 to 1966 RALLY PACS - A HISTORY - PART II

(READ AFTER PART I)

FORD PARTS DEPARTMENT

Once an owner had gone through the Accessory, and/or the High Performance Catalogs, his next stop would likely have been his local Ford Dealer.

1965 - After January, 1965, the Parts Counter would have had the 1965 "Only" Parts and Accessories Catalog (single year MPC). When the Parts man would look up the Rally Pac, he would find three listed (picture #11) ; C5ZZ-10B960-B (6cyl, 6000rpm), C5ZZ-10B960-A (8 cyl, 6000 rpm), and C5ZZ-10B960-C (8 cyl, 8000 rpm). Note that the "-A" is in addition to those shown in both the 1965 Accessory Catalog, and in the 1965 High Performance Catalog.
Once the desired Rally Pac was selected, the Parts Counter man would have checked the price. In the Ford List Price Book dated 11/65, he would find that C5ZZ-10B960-B, -C,   -D, and -E were each listed at $75.95.

1966 - Starting in January of 1966, the 1966 "Only" MPC was available. When the Parts man looked at this, it shows that two Rally Pacs were available (being "1966 Only", none for 1965 were shown) ; C5ZZ-10B960-E (6 cyl, 6000 rpm), and C5ZZ-10B960-D (8 cyl, 8000 rpm), both for 1966, yet still retaining the C5ZZ prefix. Note that a new suffix, "-E" now appears (picture #12).
Again, after the desired Rally Pac was selected, the Parts Counter man would go to his Ford List Price Book. The one dated 11/66 shows that C5ZZ-10B960-B, -C, -D, -E, -F, and -G were all listed at $74.10 each.

1967 - Once again, starting in January of 1967, a single year MPC, 1967 "Only", was available. Being for only 1967, no Rally Pac was listed. At this point, the Parts man had to rely on the 1966 MPC.
After about February of 1967, the first issue of the 1960-68 MPC was available (initially, this of course only covered up to 1967, later "Changes", Revisions, updated this to cover 1968 models also).
In the 1960-68 MPC, two  Rally Pacs are shown ; C5ZZ-10B960-D (for 1965/66 before 2/1/66 with ammeter and oil pressure gauges, 8000 rpm, and C5ZZ-10B960-F for 1966 from 2/1/66, 8000 rpm.

ADDITIONAL INFORMATION

The following information is additional to the above, and more applicable to those restoring their car.

Electrical Assembly Manuals -

1965 - For 1965, the Electrical Assembly Manual has 2 pages on Rally Pac's. The first shows the "high profile" typical 1965 type (picture #13). No details in regard to markings on the tachometer face are shown, however, 3 different Rally Pac's are listed. C4ZF-10B944-R (8 cyl) ; C4ZF-10B944-F (6 cyl) ; and C5ZF-10B944-C (8 cyl). Following the "-C" Engineering Number is the note "Hi-Performance". However, based on what we have seen above, I believe we can say that the one noted "6 cyl" is 6000 rpm, and one of the ones noted "8 cyl" is 6000 rpm and the other is 8000 rpm.

The second sheet (picture #14) in the 1965 Electrical Assembly Manual (page E5-8617-2) on Rally Pacs, shows an illustration of the "low profile" type. Again, nothing specific is shown in regard to the tachometer printing. Engineering Numbers of 3 Rally Pacs are listed ; C5ZF-10B944-JW (8 cyl, 6000 rpm) ; C5ZF-10B944-HW (6 cyl, 6000 rpm) ; and C5ZF-10B944-GW (8 cyl, 8000 rpm). Following the "-GW" Engineering Number we once again see the note "Hi-Performance".

Interestingly, unlike the pages in the 1966 and 1967 Electrical Assembly Manuals, those in the 1965 do not have drawing dates (or Revision dates) noted. However, on page E5-8617-2 that shows the "low profile Rally Pac, is the note "1965 1/2 Models". This recognizes the addition of the "GT" and "Interior Decor" Options, which require the "low profile" Rally Pac in order to have an unobstructed view of the gauges.

1966 -  In 1966, there is only one sheet (picture #15) in the Electrical Assembly Manual for the 1966 Rally Pacs ; sheet E6-8617-1. This sheet is dated 7-7-65 and has the note "Supersedes 4-8-65" (which one would think is most likely sheet E5-8617-2 noted in "1965" ; however, that sheet already notes that item 1 on that sheet is C7ZF-10B944-JW,-HW, and -GW, which is shown as the reason for the revision on the 1966 sheet, having been revised from "-JW, -HW and -DW).

Ford O.S.I. Catalogs -

These are catalogs that Ford issued, initially once a year or less, but starting in 1962, at least twice a year, usually in January and July.  These OSI (Obsolete - Superseded - Interchange) catalogs listed the disposition of existing parts, by Part Numbers. If the Part Number wasn't listed, then this usually, but not always, meant that it was still available. Part Numbers were designated as either "NR" (Not Replaced - Obsolete),  "R/B" (Replaced By - Superseded), or "mw" (Mix With - Interchange). A "sample" page from the July 1967 OSI Catalog is shown in picture #16.

These descriptors are fairly evident ; "NR" means that the exact part has been discontinued. "R/B" means that either the original part has had some minor revision (designated by a change in the suffix - -A to -B, to -C, etc.), or that a newer part (and sometimes an older part) has been found to appear almost identical, and perform, or better perform, the same function,  "mw" means that the original part can be replaced by a part that may not even appear the same, yet will perform the same function as the original part.

These ongoing parts dispositions are why, when looking for a part for your restoration that is either identical, or at least as close to Factory as was available, one needs to use a Parts and Accessories Catalog (MPC) that is as close to the year one is restoring. For example, there were single year Parts and Accessories published for each year from 1958 through 1967 (possibly later, but I don't have any later than 1967). As these were all printed in January of the Model year, even then I have found changes in a part's disposition that occurred between the Model year introduction and January. I have seen this in my 1957 cars, as well as in my 1966 and 1967 Mustangs. And of course, any dispositions that occurred after January of the Model year, would not appear in the single year MPC's.

This is where the OSI catalogs can be helpful. For a part in question, that part can be looked up in the OSI catalog to see if it was replaced by some other part, or if there has been a revision to an existing part (change in suffix). Likewise, the part in question can be "reverse-engineered" ; the part in question can be looked up in the "Disposition" column, and see if it had replaced an earlier Part Number. Obviously, the OSI won't tell exactly when the change occurred, but will give you a range ; ie, between July 1966 and January 1967, etc. Unfortunately, Ford wasn't always "johnny on the spot" in posting these changes in the OSI catalogs, as I have found some that showed up in a January MPC, but didn't show up until the next January's OSI catalog. Nonetheless, they are another "tool" for us to use.

That all being said about the history and use of OSI catalogs, back to our specific "case at hand" ; Rally Pacs. Following are summaries from an OSI from each of the years 1964 through 1969, specifically addressing Rally Pacs :

Jan 1964 - No listings

July 1965 - Shows that C5ZZ-10B960-A was R/B C5ZZ-10B960-C

July 1966 - Same as 1965 ; no additional dispositions.

July 1967 - Once again, shows that C5ZZ-10B960-A is R/B C5ZZ-10B960-C, but in addition, shows that C5ZZ-10B960-C is "NR".

Additionally, C5ZZ-10B960-E is shown as "R/B" C5ZZ-10B960-G, which in turn is shown as "NR".

July 1968 - C5ZZ-10B960-B, -C, and -G are all shown as "NR".

July 1969 - C5ZZ-10B960-B, -C, -D, -F, and -G are all shown as "NR".


SUMMARY/ CONCLUSIONS


Based on all of the information presented above, one can make the following statements/ conclusions/ assumptions :

1)  At the time that the 1964-1/2 Mustang was introduced (April 1964), there were 3 "high profile" Rally Pacs available :

       C5ZZ-10B960-A  (6000 rpm for 8 cylinder)

       C5ZZ-10B960-B  (6000 rpm for 6 cylinder)

       C5ZZ-10B960-C  (8000 rpm for 8 cylinder)

2)  By the time that the 1965 Models were actually introduced, the 6000 rpm, 8 cylinder Rally Pac had been discontinued and replaced by the 8000 rpm version ("-C").

3)  With the mid-year introduction of the GT and the Interior Decor Option (both shown in the 1965 Sales brochure dated 4/65), the "low profile" Rally Pac also was available. These had Part Numbers of C5ZZ-10B960-D (for the 8000 rpm, 8 cylinder), and C5ZZ-10B960-E (for 6000 rpm, 6 cylinder).                                                                               
Both the 4/65, 1965 Sales brochure and the 8/65, 1966 Sales brochure show the "low profile" Rally Pac with numerical markings every 500 rpm.

4)  A look at the 1966 High Performance Catalog (which has no exact date, only "Copyright 1966"), shows several interesting items ; first, the "high profile", 6000 rpm, 6 cylinder Rally Pac (C5ZZ-10B960-B) is not listed (this could possibly be because this is a High Performance Catalog, and 6 cylinders were not considered "High Performance" ; this is most likely the case since this does appear in both of the Ford List Price books dated 11/65 and 11/66). Secondly, and probably most interesting, is that 3, "low profile" Rally Pacs are listed :
   
        C5ZZ-10B960-D (Before 2/1/66, 8 cylinder with indicator lights)

        C5ZZ-10B960-G (From 2/1/66, 6 cylinder with indicator gauges)

        C5ZZ-10B960-F (From 2/1/66, 8 cylinder with indicator gauges)

5)  In looking at the 1960-68 MPC (page dated June 1968), it shows that only 2 Rally Pacs were available, and both noted for 289's :

       C5ZZ-10B960-D ("8000 rpm Before 2/1/66 ; Black, Paint to match. Use on vehicles with ammeter and oil pressure gauges".

       C5ZZ-10B960-F  ("8000 rpm From 2/1/66 ; Black, Paint to match. Use on vehicles with ammeter and oil pressure gauges".

6)  Finally another look at some of the later OSI Catalogs (remembering that many times listings lagged the part's actual disposition).

   July 1967 - This reiterates that C5ZZ-10B960-A was Replaced By C5ZZ-                 
             10B960-C, but in addition, shows that sometime between July 1966
                      and July 1967, C5ZZ-10B960-C was designated "NR", and that     
             C5ZZ-10B960-E was Replaced By C5ZZ-10B960-G, and that
             subsequently, C5ZZ-10B960-G was designated as "NR.

   July 1968 - This reiterates that C5ZZ-10B960-B, -C and -G have all been
             designated "NR".

   July 1969 - This now shows that besides the ones shown in the July 1968
             OSI Catalog, C5ZZ-10B960-D and -F have been designated as "NR".
             Thus, somewhere between July of 1968 and July of 1969, no Rally Pacs were available as Service Parts (other than what a Dealer may have on its Parts shelves, of course).

Now, in getting back to the OP's initial question about the numerical markings on the "low profile" tachometers, based on the above, I believe we can say that the "low profile" tachometers before 2/1/66 (C5ZZ-10B960-D, 8 cylinder, 8000rpm) and C5ZZ-10B960-E (6 cylinder, 6000 rpm) were numerically marked every 500 rpm, and after 2/1/66,  the "low profile" tachometers (C5ZZ-10B960-F, 8 cylinder, 8000 rpm and C5ZZ-10B960-G, 6 cylinder, 6000 rpm) were numerically marked every 1000 rpm.

While I have no pictures, TSB, Special Service Letter, etc. to confirm this, I see no other reason for the change in the suffixes of the Part Numbers.

As was mentioned earlier in this thread, the only "real way" to confirm this is to find NOS examples which have their Part Numbers or dates printed on them.

I hope this "exercise" is of some help. If nothing else, it should show how one "simple" part can become so complex.

Bob

[J_Speegle]

Of course as a possible dealer installed option an earlier version that was sitting on the dealers parts department's shelves could find its way into a later car adding to some of the combinations we sometimes, though rarely, see.

Thanks Bob .... LOTS of info about the brochures, documents and numbers.

[jwc66k]

Excellent writeup. You need to consult with Jeff and get this formatted for entry in the library - after you correct this:

1965 - For 1965, the Electrical Assembly Manual has 2 pages on Rally Pac's. The first shows the "high profile" typical 1965 type (picture #13). No details in regard to markings on the tachometer face are shown, however, 3 different Rally Pac's are listed. C4ZF-10B944-R (8 cyl) ; C4ZF-10B944-F (6 cyl) ; and C5ZF-10B944-C (8 cyl). Following the "-C" Engineering Number is the note "Hi-Performance".  These numbers shown are of course "Engineering (or identification) Numbers", and not Part Numbers.

Ford does have a unique numbering system, or numbering systems. Simply put, the part numbers shown on the Osborn produced "Mustang Assembly Manuals", all years, all sub-systems (Electrical, Interior, Body, etc) are the real, actual, factory ordered, factory incoming inspected, factory marked, factory inventoried, factory installed, factory quality controlled, factory everything part numbers. The part numbers shown in the Ford Car Parts (aka - MPC) are stock numbers, the locating number on a shelf, used by the Ford service department personal to get a part. If there is no part on the shelf (aka - out of stock), the service department typically orders a replacement from a district parts depot. If the parts depot is out of stock, they will order it. Note: all part numbers up to here are in the (general) format of C5ZZ- xxxx-y (an example). If a new replacement part is needed by the depot, the document supporting C5ZZ-xxxx-y is looked up and it will refer the part to be built to the so called engineering number - C5ZF-xxxx-y (also an example), from which it will be built, marked, inspected, inventoried, almost exactly like the original part was made for the factory - except a new step is added, mark with the service part number so it can find its way to the shelf.
C4ZF-10B944-R, C4ZF-10944-F, C5ZF-10B944-C are real part numbers, C5ZZ-10B960-B, -C, -D, -F are stock number.
Jim

[Morsel]

Wow, thanks for this info Bob... It sounds like I'm pretty good with the every 500 RPM 8000K tach for my cars build date, considering I'm right on the cusp of the change over date if what you've found... I'm sticking with what I have

Appreciate the detail, a fun interesting read.

Jason

[steve_f]

Thanks for all the research and detail Bob! I have a question about the high profile rally pacs. All of the rally pacs in the pictures, except for possibly picture #2, have Rally Pac on the bridge and Mustang in the tachometer face. I have a dealer one (as Jeff mentioned probably on the dealer's shelf back then) on my 1965 SJ GT with nothing on the bridge and Ford on the tachometer face. Did you find any information about having Mustang or Ford on the tachometer face in the dealer accessory Rally Pacs? Thanks.
Steve

Jeff, don't know if this is a topic for a new thread. 

[196667Bob]

Steve : I'm not at all surprised at your question.  As a matter of fact, over the years I have also seen both types in '65 Mustangs. I had always thought that the reason was probably the difference between Factory installed Rally Pacs and Accessory Rally Pacs. Therefore, I made it a point to try to find something that would support, or refute, this theory.

When looking at all of the details, I found only a "mixed bag of tricks". As you noted, both the 1964-1/2 and early 1965 Sales brochures appear to show the high profile Rally Pacs with the words "Rally Pac", and assumedly, the word "Mustang" (although that is hard to confirm in looking at the pictures). Yet, the 1965 Factory Assembly Manual appears to show one like you have pictured, without the words "Rally Pac". In addition, the high profile Rally Pacs shown in the 1965 Accessory Catalog, and in both the 1965 and 1966 High Performance Catalogs, clearly show the Rally Pac with the words "Rally Pac",  and "Mustang".

While the appearance of high profile Rally Pacs with the words "Rally Pac" in both the Sales brochures and in the Accessory Catalogs seems to refute my theory, knowing that many times Ford "staged" items for Sales brochures, it is possible that a Service part could have been used in the brochure pictures.
Unfortunately, unlike the low profile Rally Pacs where the ones after 2/01/66 had a change in the suffixes of the part numbers (which lead to my premise that Rally Pacs after that date had numerical markings every 1000 rpm's instead of the previous 500 rpm markings), there was no such change in part numbers for the high profile Rally Pacs ; the initial C5ZZ-10B960-B and C5ZZ-10B960-C Rally Pacs were available until sometime between July 1967 and July 1968, when no more high profile Rally Pacs were available (other than what might be on a Dealer's Parts Department shelf).

Once again, we are left with the only known way to determine the difference, and when it might have occurred, is to find known, dated examples of both Factory and Service part high profile Rally Pacs.

While I haven't researched my TSB's yet, I would think it unlikely that an "appearance change" such as this would show up in a TSB.

Possibly, someone else might have some documentation on this difference between the two types of high profile Rally Pacs.

Bob

[Bossbill]

Other than having an SAI modified Rally Pac in the Shelby I have no skin in this game.
However, that's a really impressive piece of work, Bob.
Enjoyed reading it.

[C6ZZGT]

Excellent writeup. You need to consult with Jeff and get this formatted for entry in the library - after you correct this:Ford does have a unique numbering system, or numbering systems. Simply put, the part numbers shown on the Osborn produced "Mustang Assembly Manuals", all years, all sub-systems (Electrical, Interior, Body, etc) are the real, actual, factory ordered, factory incoming inspected, factory marked, factory inventoried, factory installed, factory quality controlled, factory everything part numbers. The part numbers shown in the Ford Car Parts (aka - MPC) are stock numbers, the locating number on a shelf, used by the Ford service department personal to get a part. If there is no part on the shelf (aka - out of stock), the service department typically orders a replacement from a district parts depot. If the parts depot is out of stock, they will order it. Note: all part numbers up to here are in the (general) format of C5ZZ- xxxx-y (an example). If a new replacement part is needed by the depot, the document supporting C5ZZ-xxxx-y is looked up and it will refer the part to be built to the so called engineering number - C5ZF-xxxx-y (also an example), from which it will be built, marked, inspected, inventoried, almost exactly like the original part was made for the factory - except a new step is added, mark with the service part number so it can find its way to the shelf.
C4ZF-10B944-R, C4ZF-10944-F, C5ZF-10B944-C are real part numbers, C5ZZ-10B960-B, -C, -D, -F are stock number.
Jim

C4ZF-10B944-R, C4ZF-10944-F, C5ZF-10B944-C are real part numbers, C5ZZ-10B960-B, -C, -D, -F are stock number.
.
.
I beg to differ---as a current Ford parts dude,we never refer to the eng# as a part number !
.
.
BOB--Phenomenal couple of posts !

[jwc66k]

I beg to differ---as a current Ford parts dude,we never refer to the eng# as a part number !

Call it what you want. The reality is that number Ford Service Departments use is a stock number. You cannot recreate the item from that, you can only recreate the item from the engineering number which is what originally went into the car at initial assembly.
Former Ford dude.
Jim