Manufactured from premium materials and machined to exact tolerances, these roller lifters are used on the 720 horsepower ZZ572 and 620 horsepower ZZ572 crate engines. A heat treatment process further increases their strength and durability. The vertical bar feature maximizes lifter bore contact to provide more surface area, which results in less wear. In addition, material is removed from non-critical areas to produce a strong, lightweight lifter that's a reliable choice for both racing and street machines.