[robnolimit]

There have been a lot of spring questions lately, so here is some info. There are two ends of the 'spring' range when it comes to suspending a vehicle. You can use a stiff spring, it will have very little "static compression" (the amount of spring compression from it's free height to the comressed height at ride height), or a soft spring with a lot of static comression. You have to be carefull when you talk about static compression, becausethere are two kinds in play here. 1: Static SPRING compression, and 2: Static SUSPENSION compression. The difference has to do with the leverage ratio on the spring. I try to shoot for 5" of total static suspension compression as a starting point. With a coil spring, this would be 5" of suspension travel from a full droop position with no spring load to ride height. If the spring is compressed some at full droop, this must be added in.
This will give a nice smooth ride and good performance. Now here's the tuning rule. If your truck has a push (understeer), the general rule is to go softer springs and shocks with firmer compression. This may seam backwards, but it works. If the truck turns in great, and you have no tire slip, then you can go firmer on the springs, or a bigger sway bar.
If the leverage ratio on a C10 arm is 2-1, which is pretty close, and the truck has 3025 lbs on the front end (4000 lb total, with 55% front weight). That would be 1512 lb per side in front. With a 2 to 1 ratio on the A-arm, that puts 3025 lbs of pressure on the spring at ride height. If you were shooting for 5" of suspension compression, that would be 2 1/2" of spring compression (2 to 1 ), you would need a 1210 lb spring. (3025 divided by 2 1/2).