Safely increasing cam lift or maximum engine RPM will require new valve springs. For example on the 3800 we use LS1 "behive" valve springs which means that when running new springs you will also need our LS1 retainers.
These 90# springs are OEM GM LS6 springs. The LS6 engine comes from the factory with .550" of lift and spins to 6500 RPM to give an idea of what these springs were made for with factory reliability. The seat pressure is lower than the Comp Cams 105# springs but the spring rate is higher so they do work well for more aggressive ramp rates. There springs work well with the VS and NIC cams when shifting at 6000 rpm. Because of the higher spring rate, timing chain dampener life is lower than with the 105's.
Why install valve springs?
When boost is increased, that boost is pushing on the back side of the intake valves, therefore your actual valve spring pressure is reduced. So when you add valve springs it allows you to rev higher and increase your boost without losing any performance to valve float. If you are boosted and want to shift above 6000rpms, then we would recommend the Comp Cams 136# or Crow 130# valve springs instead.
Some users have reported that in naturally aspirated applications the LS6 springs have excessive noise and cause false KR readings at certain rpm points. However we have not experienced this.
1.80 recommended install height.
These are all packaged in sets of 12.
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