[robnolimit]

It depends on shock lenght. As a golden rule, I try to get 5" of static spring compression at Ride hieght. The rear of a c-10 is about 1500 lbs. half per side = 700. If you could get 5" of static compression, that would be a 120 lb spring. Most set-ups won't allow for that, 3" to 3 1/2" is more realistic, 700 div. by 3 = 233lbs/in spring, or 700 div. by 3 1/2 = 200lbs/in spring.