Truck Repair: STC VALVE KIT, valve kit, white spring

Question
CLIFF I PURCHASED A REBUILD KIT FOR MY STC VALVE
I HAVE A L-10 CUMMINS CPL # 1447 MY QUESTION IS THAT IN THE KIT THERE ARE 4 DIFFERENT SPRINGS.
THESE SPRINGS ARE COMPRESSON TYPE THEY ARE COLOR CODED IT LOOKS LIKE THEY RANGE FROM LIGHT DUTY TO HEAVY DUTY COMPRESSON.HOW DO I KNOW WHICH ONE I SHOULD USE WHEN I REBUILD THIS STC VALVE.

Answer
The STC valve kit is for ALL engines.Yes the springs are color coded depending on which engine it goes in.I would say the blue/white spring.Clean old spring good & see if you can verify color code.With out serial number I can not tell you exactly but im sure it is that one.