On the left is a new set of Comp Cams short-travel hydraulic roller lifters. The short-travel lifters are the retrofit style, meaning they have connecting arms to prevent them from turning. The short-travel lifter helps with higher-rpm engine revs and will stabilize the valvetrain because of the shorter travel. On the right are Comp Cams hydraulic roller lifters for the Gen II SBC. These are standard travel and have many applications.