Spring rate help for bilstein coilovers

[dolf]

I am planning on installing the chicane lm from ATS with bilstein coilovers. I need to know the proper spring rates to work with GW cat 5's out back. I have a 383 sbc with al. heads and intake as well as an aluminum radiator. It is a DD street car but I regularly autocross. Will 475 work or should I still go with the 550?

[dolf]

So will the heads, intake, rad, and possibly CF hood offset the weight enough to go with the lighter spring? Or will the 550 be a better front to rear balance of spring rates with tthe cat 5's? Little help guys...

[67bird]

I would try asking Tyler at ATS. I am going to run a similiar set-up, except I have DSE springs in the rear. I am running a Pontiac 505,but he recommended 600lbs. for me.