Dimensions are same for Coupe & Sedan. You should measure your springs to confirm the dimensions listed below. Only "C" is affected by age

Order Form for Flex-Form



1200 Sedan/Coupe
A-dimension overall = 1110mm
B-dimension center pin = 19-5/8"?
C-dimension arch height = 2"?
D-dimension chord = 44 3/4"
E-dimension bolt diameter = 11mm? OR front=5/16", back=25/64"
F-dimension width = 50mm
Car weight = 1640 pounds
Axle Percent Rate: 54/46

Spring Rate is custom order, you decide. For comparison:
* Sedan,Coupe (stock): 109 lb/in
* Nissan Competition: 114 lb/in
Flex-form reportedly feels stiffer than same rate in a leaf pack
NOTE: Leaf spring rate doesn't change with age, instead it sags (camber is reduced)