I keep seeing fellows talking about the duration of a cam increasing with the changing of the rocker arm ratio and I need someone to make sense of this to me. Duration is measured at the cam, not the rocker arm or valve. Every time the cam comes around, the lifter is engaged at the same point on the lobe, so even if you had 10:1 rocker arms on the motor, it would only change the lift, not the duration. Can someone correct me on this if I'm wrong and explain it to me?
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