School me on Leaf spring sizes

[Nefarious Cohort]

Greetings,
I recently was given a 76 GMC Jimmy, its been rode hard and abused to the point that there are a few broken leafs in one of rear packs and a front shock mount torn away.

After searching and reading many a post here about spring packs and swaps I often see where 52" or 56" springs are mentioned.

What is the significance between the spring sizes and what makes them desirable one over another?

Since I am going to need to replace the rear packs I might as well replace the fronts too (since they were all abused together), I figured I would head to the local wrecking yards looking for a suitable donor vehicle.
Is there a preferred year/make blazer/suburban/PU I should be looking for?

I do appreciate your time and help

Thanks

 

[Silver84k5]

The rear springs in that blazer are 52" inches long. A lot of people take the rear 52" inch springs, and move them up front, and replace the rear springs with a 56" inch spring pack. ( i belive 56"s came out of 3/4ton trucks) youll just have to go to the junkyard with a tape measure.

I put the 52"s up front because they give you approx 4 inches of lift, and flex fairly decent. I made some new spring hangers in the front, and some longer shackles for the rear of the front spring...

There are two reasons I put 56"S in the rear, a Longer spring will give you more suspension travel, and since the center pin is off set, you can run the spring backwards, and gain 4 inches of wheel base i belive ( been a long time since i did and cant remember all the numbers ;P)

to put the 56"S in the rear, i used the stock spring hanger, and an ORD shackle flip,
There is a right and a left shackle flip bracket, all you have to do is swap sides with them ie. run the left one on the right frame rail and the right one on the left frame rail. voila, your done. i think i might have moved them back some too, to get the shackle angle that i wanted, like i said its been awhile.

im sure there is a write up on here somewhere.

 

[Nefarious Cohort]

Silver84K5, Thanks! That sure does clear a lot up and will help me.

I can also refine my searches now that I know better what I am searching for and gather up some more intel.

Much appreciated
Nefarious