Ofna 3 Shoe Clutch Question

[GilBeQuick]

Just got the clutch today, part # 10012 . With the clutch kit comes 2 sets of springs, one silver and one black. What the clutch doesn't come with are directions. I'm guessing one is stiffer than the other, but which is which? Also the clutch comes with washers. Do I need to put the washers on boths sides of each spring?

 

[GilBeQuick]

OK well I figured out the black springs are the stiffer ones.
The 6 washers it comes with are clutch shims. Why would you need to shim your clutch? I've had several engines and I've never had to do this before, is it something specific with aluminum clutches?

 

[terminator2004]

qwer

hare you shure the black one is the stiffer one