Good morning:

I have to ask this question: How often should I replace valve springs? I have a 500 cu. in. iron headed Mopar with a set of Comp Cams 925-16 springs on a solid cam with 640 lift. I run these about .035 from coil bind. They are off for inspection now (after about 280 passes). The seat pressure is unchanged but I notice the free length varies .020. They are still square.
Should I replace them because its time or because they are .020 short or am I being paranoid?
Are there any general rules about replacing valve springs?

I'm under the impression that .060 is as close to coil bind that you should run on a good spring I have run a bunch of springs at .100 clearances and saw 15 to 30 lbs pressure loss after a lot of use. I reshimmed them to get the pressures back and ran them some more and saw no loss of pressure after that. All of those motors had BB stainless valves in them, no lightweight titanium valve experience on my part