If you can't tell by looking at them, set them up on an engine and measure them. First, measure the lobe lift on a cam. Say the lobe lift is .300". Then measure the lift at the valve side. If valve lift is .450, then you have a 1.5 ratio (.300 x 1.5). If the valve lift is .480, then you have a 1.6 rocker (.300 x 1.6).