C7ZA Leaf spring ID help

[brandosaac]

i have a pair of leaf spings im trying to properly identify, and im not coming up with much information.
Anyone know what C7ZA-5556-AS might be originally from?
Thank you

[J_Speegle]

At first look one of the applications appears to be a 67 + 68 S code fastback  Mustang. With the date and stamping pattern they may have come from a Dearborn or NJ car built late in the 67 production year or early 68

Looking further at a Aug 67 MPC it lists the applications as
Mustang

67 390 and 289 with improved handling from Oct 26th - fastback and convertible

69 390 - fastback
68 289, 302 4V & 390 4V - convertible
68 390 2V with improved handling - fastback and convertible

Hope this helps