Build Sheet Question - Leaf Springs

[Dennis Y]

Would be interesting to see a side by side comparison of the Mach 1 spring that the car left the factory with and the spring A.O. Smith put in as far as length of the individual leaves. We know the top is the same and the bottom is different but what about the other two and did it retain the 550# rating.

Also, was ford making their own springs back then or using an outside vendor? If made in-house, did they also supply the Shelby spring to A.O. Smith or did Smith use their own vendor. Is it JRS spring that is also located in Michigan? More questions than answers.

[J_Speegle]

Would be interesting to see a side by side comparison of the Mach 1 spring that the car left the factory with and the spring A.O. Smith put in.

Also, was ford making their own springs back then or using an outside vendor? ............

Ford used multiple sub contracting companies to supply leaf springs for the many different needs and al those plants around the country.

[Coralsnake]

AO Smith would not have chosen the springs. That was Ford.

Ford built the car with their springs and AO Smith replaced them with the Shelby specified springs.

I have been told the springs were made by Rockwell, but I have not confirmed this yet. The small keystone stamp on them maybe a clue.

[TLea]

The vast majority were special leaf springs that had the bottom and two upper a different length compared to regular Mustang . The typical 69/70 Shelby bottom leaf was marked S9MS 5560 A. There are two other different markings that I am aware of also. Yes as Pete mentioned they were marked with a sprayed on white marking encompassing the spring eye. 

Ed will clear this up but IIRC some were marked C9?

[Bob Gaines]

The vast majority were special leaf springs that had the bottom and two upper a different length compared to regular Mustang . The typical 69/70 Shelby bottom leaf was marked S9MS 5560 A. There are two other different markings that I am aware of also. Yes as Pete mentioned they were marked with a sprayed on white marking encompassing the spring eye. 

Ed will clear this up but IIRC some were marked C9?

S9MS,5RS68 and C9ZX are the ones I am aware of.

[Coralsnake]

Mr Gaines are the C9ZX Shelby unique?

[TLea]

Mr Gaines are the C9ZX Shelby unique?

Yes

[Coralsnake]

Does anyone have pictures of these?

[Special Ed]

The c9zx show up late but look the same as s9ms.  I once thought auto vs 4-speed staggered shocks were the change ID #. but thats not the case either or big suspension change but i ruled that out also. So i think its more of a ford # changeover just like 69 b9 parts started off kkx then went to c9zx same part just a running change.

[Bob Gaines]

Would be interesting to see a side by side comparison of the Mach 1 spring that the car left the factory with and the spring A.O. Smith put in as far as length of the individual leaves. We know the top is the same ang the bottom is different but what about the other two and did it retain the 550# rating.

The two inner leaf's are longer on the 69/70 Shelby at 46" on the upper and 32 1/2 on the lower compared to a regular Mustang regardless of year (65-70) or application. I don't have the measurements on the earliest 5RS68 marked Shelby leaf spring.

[shelbymann1970]

My May 6 built at Dearborn plant car  springs.not  sure on the conversion day at Smith.  I just pulled this down from my attic as a local guy is going to reproduce them and needs one of mine for dimensions.,

[shelbymann1970]

69 Shelby spring on the left and 1968 GT500 FB spring on the right. Not sure if a 69 would have diff spring lengths than a 68

[Special Ed]

69 shelby 2 round hole wraps vs mustang 3 square hole wraps

[J_Speegle]

69 Shelby spring on the left and 1968 GT500 FB spring on the right. Not sure if a 69 would have diff spring lengths than a 68

Yes the length of some of the leaves are as well as the hardware as Ed mentioned

[sg66]

69 shelbys were designed to have the new wide low profile f-60-15 polyglas gt tires and early shelbys had tractions bars so i think the new leafs were designed for better traction with new wide tires. 69 shelby leafs only used 2 round hole (not square hole) spring wraps not 3 like other year springs and bottom leaf lays flat and dont use a sring wrap. The front eyelet had white paint sprayed on the front end and the later cars started using c9zx bottom leafs along with the s9ms and i never could figure out why #s change as gt 350 vs gt500 vs 4-speed vs auto as nobody that i know of has figured out a pattern but the very early cars had 5rs68

Not sure how much this helps but page 35 calls out a 69 GT350/500 spring with less free arch springresearch.org/pdf/volume_17.pdf