Ferrea Valve kit is necessary If you plan on revving your Honda k20 over 7400. They are also recommended if you are running the step 2 camshafts. Running higher RPM will run into valve float and potentially crash the valve into the piston. 8100 rpm with big cams have not been an issue for these springs.
Ferrea products have long been the standard for top of the line cylinder head components.
Includes:
S10165- 16
E20056- 16
SL1151- 8
SL1152- 8
K10116- 16