front springs for GW/j-truck - quick help, please!

[Proj76J10]

i'm looking for some stock front springs to do an SOA conversion on my j-truck. (my rig came with stiff-as-boards lift springs on it when i got it).
my first question is: is there any reason why GW front springs won't work for this purpose? (i called teamGW and they said that they are very different, for some reason that i have no idea why)
second question: i have a set of old stock front springs that are still on my j-truck parts rig. the catches are that the truck had a 6-cylinder in it, and i'm not so sure how different the spring rates are, and if these would be viable springs to use. additionally, these are rather old springs and i have no idea if one side has sagged more than the other, etc... i'd also have to take the packs apart to clean them and install new bushings, retainer clamps, and anti-friction pads. cost-wise, i'd much rather go this route because i'm quite the CB.
thoughts?
thanks, all!!!

[J10_Jimbo]

I think you would be wise to have the used springs rearched at a good shop and have them insert an extra leaf. Years ago when I did a SOA I used 6" chevy lift springs, a 6 degree wedge and a shackle swap to clear 40's. The stock springs should at least be cleaned and inspected for cracks, and have a new pin installed.

Hope this helps

[Proj76J10]

what's the purpose of the extra leaf? i'm not looking for additional lift on top of the SOA. in fact, i'd like to have as low of a spring rate as possible, as this truck is going to be my DD and daily tow rig.

[J10_Jimbo]

If I remember right moving the spring from bottom to top is changing the flex of the metal and with out an extra leaf for support the spring would eventually bow up (negative arch) and break. My experience was, an add-a-leaf spring doesn’t give you much lift, but helps the other springs retain their arch. I would be happy to hear others advice on this too.