1.5 ratio rockers or 1.6?

Thanks for the responses guys. Changing the ratio will not change the actual duration but will change the effective duration...this much I am certain of. The valve lifts faster so airflow gets underway quicker.

383dart. You talk about grinding for clearance. Just to make sure I understand, the 1.6 rockers work by shortening the pushrod side of the rocker arm? If thats true it would make sense that the holes would have to be clearanced. I'm kind of confused though why intakes would need it more than the exhaust.