I had 6 springs, 6 shims, and 4 spring seat parts.
There were 4 springs on each side, 1 large, 1 med, 1 small, and 1 real small. I left the small spring out because the directions say to remove all springs except the large one.
I removed the shim under the larg spring, and yes, the idle dropped about 150 rpm's. I just increased the idle speed on the back of the pump.
Feels like a different truck now!!!
I have noticed the truck seems to prefer the upper RPM's now. I have to pay a little more attention to the speedometer, I've found it well over 80mph a few times when before, I used to have to push it to get there.