Ditto!

 

I deal in Eibach springs. What is important is the diameter if the spring. If you are using a 2.5" spring than a 600 is doable. If you are using a 2" spring, the highest rate that can be had is 550.

 

FFR stocks them, as I got them with my kit. They came in 2 1/2" diameter, though, maybe not compatible with your spring perches.

In an earlier car, I bought #600's from Blue Coil Springs at Blue Coil Gordon Levy also sells springs.
HTH

 

I think I have a set of 600lb 2.5"x8" springs.

 

If you have Pro-Shocks (like I do), contact pro-shocks directly. They have a web site.

 

FFR swapped the #450's for #600's for next to nothing for me.

Fred K