Duration will increase 1 to 2 degrees also when changing ratios. Hope this helps
To determine the change in lift when changing rocker arm ratios, divide the lift of the cam by the original rocker ratio (which gives you the lobe lift), then multiply this number by the new rocker ratio. For example, the stock Mustang 5.0L HO cam has .444” at the valve. Divide this number by the stock rocker ratio of 1.6 to get the lobe lift, .2775” and multiply by the new rocker ratio 1.72, to get the new lift of .477”.
Duration will increase 1 to 2 degrees also when changing ratios. Hope this helps
To determine the change in lift when changing rocker arm ratios, divide the lift of the cam by the original rocker ratio (which gives you the lobe lift), then multiply this number by the new rocker ratio. For example, the stock Mustang 5.0L HO cam has .444” at the valve. Divide this number by the stock rocker ratio of 1.6 to get the lobe lift, .2775” and multiply by the new rocker ratio 1.72, to get the new lift of .477”.