Guys, if you haven't figured this out techinspector1 already knows the correct answer, he is just testing us to see if we truly know. And, after all the arguments about it I can't say as I blame him for it. LOL..

Now my wade into the pond on this (and I may be wrong); cam duration is TIME (as in real time, not ignition timing), in other words it is the amount of time the given valve is open. It gets more complicated as to the relationship with the crank, but that is the basics. Rocker arm ratio has nothing to do with cam duration..