Build Sheet Question - Leaf Springs

[Coralsnake]

I think its a great contribution.

So here is what I found:

The part number for one of the Shelby springs is C9ZZ-5560-J

Am I reading this correctly?

It was marked C9ZA-5556-S if used on a Boss 302 and S9MS-5556-A if used on the Shelbys.

Its possible that Shelby didnt want to use "boss" parts, so even though the spring is the same they just rebranded it. What do you think?

https://www.boss302.com/spring.php

Now we need to find the other two versions

[Coralsnake]

Does anyone have a picture of the later C9ZX spring??

Has anyone noticed a change in the bushings on these Shelby springs?

[Bob Gaines]

I think its a great contribution.

So here is what I found:

The part number for one of the Shelby springs is C9ZZ-5560-J

Am I reading this correctly?

It was marked C9ZA-5556-S if used on a Boss 302 and S9MS-5556-A if used on the Shelbys.

Its possible that Shelby didnt want to use "boss" parts, so even though the spring is the same they just rebranded it. What do you think?

https://www.boss302.com/spring.php

Now we need to find the other two versions

I don't believe the MPC shows what was assemblyline. I believe what you are reading in the Master Parts Catalog is a case of as it has to do with a service replacement part vs assemblyline part. The Boss leaf springs are the closest thing to substitute as a service part to the Shelby leaf set is my guess and was used to service both if needed.  The Boss 302 spring when compared side by side to the S9MS leaf has the two inner leaf's shorter not to mention the curved bottom leaf compared to S9MS marked leaf set with its 2 longer inner leaf's and its straight bottom leaf. Although I have several sets of S9MS leaf sets here in my shop now  unfortunately for this thread sold all of the the  C9ZA-S leaf sets I have had over the years that i could have used to show a side by comparison.  The side by side difference is somewhat dramatic.

[Coralsnake]

Mr Gaines, thank you

So are you saying the C9ZA-5556-S and the S9MS-5556-A are not the same spring?



Im not saying you're incorrect, but it would appear they are the same as both IDs are included together

[Bob Gaines]

Mr Gaines, thank you

So are you saying the C9ZA-5556-S and the S9MS-5556-A are not the same spring?



Im not saying you're incorrect, but it would appear they are the same as both IDs are included together

As I have already said It would appear to be a case of a service replacement part vs assemblyline part given the physical differences between the two.

[Coralsnake]

Ok well, I will work on a new theory

I am full of them 😆

[Dennis Y]

There was similar information on those springs on a chart from General Spring in iirc Kansa City MO. I'll have to go back and look for it.
In reference to reply #30, another question, were the 69 Boss 302s in production yet when Shelby ordered the Mach 1s used to start building the Shelbys? Maybe B2 springs were not in production yet, but specs were known. Since both cars have a similar squat, it would seem that it could be the same spring.

[Coralsnake]

Im going to say I strongly feel like the company was Rockwell Standard



Heres a picture of a z28 Camaro stamping. Rockwell did springs for GM and Ford

Mr Gaines is saying the the Boss springs are visually different and I believe him

[Dennis Y]

Can't find the chart I was looking for on the General Spring site but their listings do show the same industry #42-503 for the GT350/500 as the Spring Research chart. General is not showing a listing for the Boss 302.

[Bob Gaines]

Can't find the chart I was looking for on the General Spring site but their listings do show the same industry #42-503 for the GT350/500 as the Spring Research chart. General is not showing a listing for the Boss 302.

I suggest you re read my post #24 and do the homework if you want to know the real  answer.

[Coralsnake]

I agree all this extra stuff is noise. It doesnt matter what other companies like Eaton, springy thingys and General are offering as replacements. ( if they even are ) We are concerned with the OEM assembly line springs.

[Special Ed]

We were working on the s9ms springs back when chris brown passed RIP ole buddy and chris had a machine shop making the unique lower flat leaf and stampping the #s since the rest of the spring can be found from other springs. I sent an odd s9ms lower leaf i had here to chris but not sure if i got it back but if someone wants to finish making the spring i can loan my s9ms leaf out.

[J_Speegle]

Just to support the discussion and add some addition information and documentation. These are from Ford and what they used to assemble the cars provided to AO Smith

Checked what is commonly referred to as the add/delete sheets and on the copies/forms I've got it shows

One set of sheets shows

Items to be selected  #9393368
Items to Omitted Rear Springs (2 Stage) 

Description REl. 1-22-69 -Per Trans. X9A-291

++++++++++++++++++++
Then looking at a later sheet dated 1-22-69 it shows. Likely the form referenced above.

Items to Omitted      Sportroof - C9ZA-5556-C or G(difficult to make out) Rate 135-141 & Load 670-710
                      Convertibe - C9ZX-5556-A                            Rate 128-142 & Load 715-775

Items to be selected/installed  Sportroof - C9ZX-5556-A                  Rate: 128-142 & Load 715-775
                                Convertibe - C9ZA-556-E                  Rate 135-141 & 710-750


It is interesting and a puzzle since the buildsheets used on the line to construct the cars at Ford still listed the standard (for the application as a Mustang) rear spring markings.
Hope this helps

[J_Speegle]

Can't find the chart I was looking for on the General Spring site but their listings do show the same industry #42-503 for the GT350/500 as the Spring Research chart. General is not showing a listing for the Boss 302.

Might have to do with the fact that the Boss 302 was only produced during the later part of the production year- sometimes referred to as a 69 1/2 so depending on when the data was collected and published that might explain it. Same thing happened with paint codes as late and mid year paint chip pages didn't include those Boss 302 exterior only colors on the sheets.

[J_Speegle]

Mr Gaines is saying the the Boss springs are visually different and I believe him

Can confirm that also with my low mileage very early built 69 Boss and others I've seen. 

Mine are marked (lower) short leaf - C9ZA-5556-S          Dated 20 days before the car was built.