The rocker arms are full-roller aluminum units (manufactured by Crane but marked as Ford Racing). The ratio for both intakes and exhausts is 1.65:1. Total valve lift is 0.822 for the intakes and 0.842 for the exhausts. The intake rocker arm uses an offset pushrod cup to clean up the geometry. Two rockers on each bank of heads require grinding to clear the corners of the valve covers. We spoke with several engine builders who agreed that this is common practice with aluminum rockers in Ford motors. It isn't a concern as long as the grinding isn't excessive. Crane will be modifying the rockers specifically for this engine, making the clearancing much less noticeable.