Spring height school me!

you need a tool somewhat like this one ..that goes in place of the valve spring..

http://www.ebay.com/itm/VALVE-SPRIN...0850115602&pt=Motors_Automotive_Tools&vxp=mtr

once you determine the height ....you can adjust the spring height with shims to get to the install height as spec or adjusted it to whatever you want or need....

the valve spring manufacturer will give you a height and how many lbs it is at that height...