To have a competition camshaft its in most cases recommended to use these stronger valve springs. You can make a choice out of single or dual springs:Single: up to 12 mm valve lift, perfect up to 6000 rpm.Double: up to 16 mm valve lift, perfect up to 7500 rpm.Extra double: Same characteristics as the dual, but they are made out of a material that offers more resistance and is stronger, resulting in higher capacity of the engine.ATTENTION! Due to the double valve springs you have to remodel the stock cylinder heads.
