[whyholdback]

http://www.moog-suspension-parts.com...il_Springs.asp

I wanted specs, since I'm welding so much more steel into my car. I first looked up what my car is supposed to have, then found them on this list. Then I found every other option with similar specs.
Mine is an '84 Trans Am, to which I'm adding SFCs, a full cage, a custom in-trunk class-3 hitch, and a custom gooseneck hitch. Not counting the cage, that's a good 300 pounds.
I also looked up the springs for a '92 GTA convertible, to give me another frame of reference.
Up front, the 5664 seems best. In the rear, my '84 should have the 5665, while the '92 convertible should have the CC635. I'm thinking I'll swap in a pair of the CC659.