Its not a issue of not working without being in a boosted application, But in a forced induction setup when selecting cams and springs you want to select the cam with the highest lift but with the least amount of duration, look at it like this, you want all the boost you can get into the cylinders(highest lift) but at the same time you need to open and close those valves ASAP as to not leak boost back out the valves(less duration) which is how long the valve is open, The stronger spring seat will allow you to keep those valves opening and closing under the most extreme pressure, were a weaker NA spring would give under those extreme loads(pressure) limiting you on power output and spool-up time, and in some cases spring failuer Is this what you were looking for KJ?? I may be off, its been a wild week Happy easter!