Unlike 289/302 Fords, both the FE big-blocks and 170/200 inline sixes have shaft-mounted rocker arms. Lubrication comes not through the pushrods but instead through pedestals and shaft. Pedestal positioning must be exact or the rocker arms won't get oil. This is an adjustable rocker arm assembly, which applied mostly to mechanical lifters. These engines came with both adjustable and non-adjustable rocker arms. The only thing available at press time is the adjustable rocker arms and cup-style pushrods.