This power steering flow control valve for GM Type II power steering pumps reduces flow from 3.2 GPM to 2.1 GPM. A perfect partner for hydroboost applications, this 7/8" hex valve reduces the "twitchy" feel that sometimes occurs when a Ford rack and pinion is used with a GM power steering pump. Note when replacing your stock valve: this valve replaces OEM valves with 7/8" hex. Zinc plated steel. Made in USA