math class needed on valve springs

[gmonde]

Originally Posted by Eman

Is the spring rate 370lbs per inch? Is the installed height 1.780? Open height can't be more than closed, what is the free height of the spring?

this is the spring I am using ,I have a installed height of 1.780 and shooting for a 170 lbs seat pressure with a close to 400lbs open ,the .100 difference should get me there but, I cannot remember the formula that will get me that number ,, its been 5 years since I built the car and my info was given to the previous owners,,
I cant remember for the life of me ,, internet search is coming up short

my lift on the cam is .457

installed Height (in):
1.880 in.
Seat Pressure at Installed Height (lbs):
155 lbs.
Open Height (in):
1.280 in.
Open Pressure (lbs):
377 lbs