Just because your open and closed pressures are 'identical' does not mean that they are from the same manufacturer. If a double spring is used we also must add that more mass usually entails more heat produced by the compression and extending of the springs during operation.
Like guy said, he over builds rather than under build, much like I "overdue" my thinking and waste my time thinking, cutting and trying on heads. Now as far as the springs it seems that most talk so far has been about just static open and closed rates along with mass but no graphing showing what length would benefit and what rate also. If you watch spintron testing in slower footage rates you will actually see how the spring moves during the rpms, I haven't spent much time yet on it but since the subject is up why not open it further into perspective. For instance what is factory rate, diameters (wire and outside diameter, inside diameter, installed height, binding height, lubrication (cooling) level needed versus what is needed for certain applications in high power high rpm with different camshaft profiles as well as solid versus hydraulic lifter configurations.
How many companies out there produce springs and retainers to go with the cam profiles they sell? How are we picking the right springs to set the valve down properly minimizing valve bounce if we don't buy the camshaft with the springs? Would we want a 'loft' scenario on some things?
