I'm swapping out the rear control arms with the urethane bushings from my convertible into my Buick. I assumed the springs in the Buick were original. But, I pulled out the dual rate springs like the one on the left. They're powder coated and don't look terribly old. The one from the convertible is on the right. It's a heavy duty spring for a 69 convertible that came from NPD. I don't know any more about it than that - it's a replacement spring, not lowering or high performance, or anything like that. I think NPD got their springs from Moog in 98 when I got this set. The Buick spring I know nothing about. Opinions and thoughts?

http://www.chevelles.com/showroom/data/500/medium/spring_compare.jpg

anyone?

Odd that you stumped the panel with this kind of question Andi

What was the question? ;)

Wire diameter looks about the same, but the progressive-rate spring has a lot more coils so it would be a lot softer, at least until loaded enough that the tight coils bind, and then it becomes a stiff spring like the convertible one.

Looks like I Stumped the Chumps :D

The cargo coils seem softer when I put some weight on them.

I think I'll try the coils on the right first, since they aren't hard to swap out. They are stiff, but made the car handle well. Part of the stiffness might have been the poly bushings in the differential ears, and the Buick will have rubber. I might actually like the softer dual rate springs, being that it's a Buick :) Hmm, maybe I'll post an update later.

I put the Chevelle coils in. Sits about the same. I spect it will handle about the same as the Chevelle. I guess I can file that last comment in the duh category :)