One of the rarest, most unique parts on a Ford Mustang GT/CS is the tail light wiring loom harness. It has a purple tag near the passenger side (right hand side) tail light in the trunk. This tag has the FoMoCo label and the letters “SXR C8ZX-14405-A”. Here’s how this part number is decoded:
C8 = 1968
Z = Mustang
X = Ford special or experimental
14405 = Vehicle engineering number
A standard Mustang tail light wire bundle part number is C8ZZ-14405-E or C8ZB-14405-E. The GT/CS has the “ZX”, which is the code for the special edition Mustang.