LSA is the angle between the peaks of the lobes exhaust/intake wise. Obviously if they are closer together there will be more time in which the intake and exhaust will be open at the same time. This is called overlap. It also has an effect on sound. Ie. the lopiness you want Both valves being open at the same time helps push exhaust out faster, and also bring new air in faster. Example: 110lsa will lope alot harder than a 114lsa all else being equal.

Duration is the amount of degrees the valve is open. Obviously the longer its open the more air/fuel can enter, and the more exhaust that can exit.

I have seen no known failures of blue stripe 918's under normal operating conditions(racing included). So long as you use them with a cam in their requirements, and give them time to heat up they should be fine. Don't do something stupid like use a 1.85 rocker arm on a tr220 like somebody did. There is a local guy who has had a T1 cam in his car for like 2-3 years now with 300 1/4 mile passes and 50k+ miles. However, to be on the safe side I'd say it'd be good to change em every year or two regardless of cam if you beat on your car alot and put alot of miles on it. But you probably really wont have to with a cam of the size we are talking. Several folks have run some serious cams on these springs up to 7k+ rpms and have checked the pressure after several thousand miles and its been fine. IMO springs are nothing to worry about unless you are approaching .600 lift. In that case I would use titanium retainers, and try and change them yearly.

 

Does anybody have a link where I can buy the LS6 cam package that includes the sprinks and install kit?