Hopefully some suspension guru knows about the stock suspension pretty well... refer to this post: http://www.j-body.org/forums/read.php?f=30&i=31299&t=31299 for basic information.

If I get a J body as a donor, which is very possible, Id like to know what kind of rates I would be working with, as its gonna be a major fab job with the motor in the rear since it weighs significantly less I wonder which factory suspension setup I should go with. Maybe eventually Ill go with coil overs, but for now, its stock jbody or whatever suspension.

What the spring rate on factory springs f/r?
Bound/rebound of strut?

ill find aftermarket info myself as comparison but I figure this is the place to start. Thanks

225/175 IIRC.. I'm sure someone will correct me if I'm wrong.
Bound and rebound are next to nothing stock, they suck. If you're willing to actaully build that thing, you should use something better than stock struts.

While I'm at it. I've though of doing a project like this myself. I probalby never will, just too much work/money. You could use the stock front knuckle on the rear. I'd switch it to a double wishbone type suspension though, build an upper arm to attach where the strut does now. Then put the shock+spring or coilover on that. More compact and stiffer design.

Double wishbone would be a little different. The whole hub assembly should be able to pivot itself, so even around a bend the tire will be able to maintain a flat contact patch. I dont think thats possible with a wishbone setup. Aleast if stock is "crap" and too light, I will be able to know how mmuch to step it up to tighten it up. I dont know if I mentioned before, but there probably will no be any sway bars, or atleast in the initial build, the car is light and low enough it probably wont make much of a difference if the springs are tight enough. The only thing we are waitinf for is a good donor car to fall into our hands from the sky.

Each tire will have a slight toe-in to maintain stability, and it will be limited to how much camber travel there will be. So it can adjust itself around corners (due to the pivot points on the hub where the upper/lower a-arm connect to it) It wont be able to move or pivot unless the suspension moves because it will be at a set amount. Too bad we couldnt do a radius rod setup to adjust caster aswell. Which will not work here