I've noticed many IROC and WS6 owners have BZW or CDB front springs but from what I've found BZX and BZY are stiffer but what cars got those?

For the rear, WS6 owners have said they have NNL springs but te NNM and NNB are stiffer.

I thought WS6/IROC got the stiffest available.

 

I don't think either of them came with the absolute stiffest available. I beleive they were offered as GM parts for the 1LE cars or anyone that wanted a siffer than stock spring.

 

Why do you want stiffer springs? If you want your car to handle better get some bigger matched sway-bars for it.

 

Don't waste your time on a bunch of used springs. They're all 10 years old or more, and have been worn out for at least the last 8 of them. Get some decent new ones from somewhere besides GM. Aftermarket ones are far better and cost about half as much.

 

Don't remeber the part number but i got some 89 iroc springs from the parts store for 60$. They are rated at 600 pound per inch which is plenty stiff for the street. I cut a half a coil off and put them in my monte. They took all the body roll outta that boat so they would be killer in a f-body.