When I restored my 67Z, I managed to find NOS leaf springs, dated NOS '478' shocks, and NOS 7.35x15 PowerCushion tires. Did not get credit for the springs and shocks in Legend judging but, hey, what do those judges know anyways? Here's a photo I found of the springs:
I faintly remember comparing unweighted height of the springs to new springs and measured about 1in difference. My theory is that the Z springs were not as high as the other models to compensate for the 15in wheel (all other models had 14in wheels).
Of all the things I miss, I miss my memory the most.
PS: They gave me 25 points (out of 4,000) for the tires, one of less than a half dozen sets in existence.