The ratio is the ratio of camshaft lobe lift to actual lift at the valve. Stock mopar is 1.5, ona fixed shaft. The true ratio of the stamped steelies are closer to 1.45 than 1.5... Aftermarket rockers come in up to 1.8, but they are not really budget...lol. Because it's a ratio of lift, meaning a range of movement over time (in degrees of rotation) when you go with a higher ratio arm, it will not only lift the valve open further but also open it faster, open it earlier, and close it later. Changing rocker ratio can mess things up with fast ratio cams if the valve springs are just able to do the work at the 1.5 ratio. So you want to make sure theres enough spring to control the movement, and the ratio is changed on the pushrod side, so you will want to enlarge the pushrod holes to avoid the pushrods hitting the heads. (especially with RPMs...)