C4 rear spring code/rate conversion chart?

Looking for some sort of conversion chart that has both the spring three letter broadcast code (not RPO code), and the rate. I'm looking to possibly stiffen up the rear on my (C4 suspended) '69.
Anybody know where I can get this info?

Thanks,
Mike

If you want the stiffest, get the 84 Z51 springs and bars. I had an 84 Z51 and it was so much stiffer than the FE1 90, night & day difference.

There is no spring rate to factory code conversion chart.

You have to cross reference the rate you want from here
http://www.vettenet.org/susp_chart.html

to the factory code by year here.
http://www.tubas.net/vette/rear-springs-fiche.gif
http://www.tubas.net/vette/front-springs-fiche.gif
http://www.tubas.net/vette/front-springs-fiche-2.gif

Newtons per meter x .0685218

V.S. Has them. Looks like they are Z51 + 10% or FE1 + 10%.

http://www.vansteel.com/index.cfm?fuseaction=shop.ProductList&SubGroup=1950

They even have the front challenge spring.

If you want any stiffer than these you'll have to go to vbp and get a custom rate.

Will a stock length spring work in your setup?

Solo said:

Newtons per meter x .0685218

V.S. Has them. Looks like they are Z51 + 10% or FE1 + 10%.

http://www.vansteel.com/index.cfm?fuseaction=shop.ProductList&SubGroup=1950

They even have the front challenge spring.

If you want any stiffer than these you'll have to go to vbp and get a custom rate.

Will a stock length spring work in your setup?

Click to expand...

I'm using a C4 rear spring on my setup, but I've had to shorten the spring each time (I've tried two different rear rates so far) to work with the stock C3 trackwidth.