1.5 & 1.6 Rocker ratios - What's the diff??

1.5 rockers lift the valve 1.5 times the lobe lift of the cam, 1.6 lift the valve 1.6 times lobe lift. Generally, 1.6 rockers are used to improve the lift of a camshaft that has low lift. They can also be used to get the valve lift into a specific head flow range. There's really not a need for them, as long as you choose a camshaft with the right amount of lift for your build to begin with. There are other opinions I am sure, but that's mine.