Brit is right the info to install the valvesprings, valves to the head is in the manual....
but I recall looking for a spec on spring resistance as you are .... and could not find it. So averaging out the resistance and seeing if one is way out is the easiest/quickest way to see if one is out of whack.......
Unfortunately having 8 sets of springs testing within spec may not save you from a spring just letting go 1000 miles after the rebuild.
