In my case the k1000h were 225 on the seat, and the cam card called for that much, yet the car responded with almost a tenth gain in ET in the 1/8th! There is a whole lot more to picking the right spring than installed seat pressure, open presure, and coilbind. Spring frequency is VERY important, along with total mass. I am no expert for sure, but just want this information available to you so you can research it, and get the most out of your motor. Dwayne Porter is one of the guys to talk to. He has dynoed a lot of motors, and has a lot of experiance in this area