Exactly but spring pressure has nothing to do with stem height. You could take all the spring shims out or add a 1/4" to them and it will change the pressure but not the height. The valve and it's length ans the seat and/or it's location will make a difference. The keepers and retainers won't make any difference to the stem height just the spring pressure. Think of it this way. If a valve is 6" long from the seat angle to the stem tip the only way the tip can be shorter or longer measured from the spring seat surface is the seat location (45° on the valve) or the seat itself has to change. When the valve is seated the stem tip height cannot be changed with springs, shims, keepers, or retainers.
