ARP — Automotive Racing Products
Born from a Problem, Built into a Standard
ARP was founded in 1968 by Gary Holzapfel, a racing enthusiast who recognised that engine failures among his peers were consistently caused by inadequate fasteners, and that nothing suitable existed on the market. Drawing on years of experience with a leading aerospace subcontractor, Holzapfel set out to change that. What began as a backyard garage operation in Southern California has grown into a manufacturer occupying over 275,000 square feet across multiple facilities in Santa Paula and Ventura, California, with more than 280 employees and thousands of part numbers covering virtually every fastener in an engine and driveline.
Manufacturing Without Compromise
ARP's reputation for zero-defect quality is the direct result of keeping every stage of production in-house. From raw material selection, using only the top two grades of premium alloys, including proprietary chrome moly steel that costs twice as much as commercial grade, through cold heading, heat treatment, centerless grinding, thread rolling, CNC machining, and metal finishing, every operation is performed and monitored under one roof. Thread rolling is carried out after heat treatment to achieve fatigue strength up to twenty times higher than pre-threaded alternatives, and nut tolerances are held to five times the aerospace standard. Fasteners are then fatigue-tested through millions of cycles, far beyond the aerospace norm, before leaving the facility.
The Fastener of Champions
ARP's customer list spans the full breadth of world motorsport. NASCAR, IndyCar, Formula 1, NHRA Top Fuel, IHRA, and countless other championships have all been won with engines built using ARP fasteners, a record that reflects not just quality, but trust at the highest level of competition. Beyond motorsport, ARP also holds a United States Government licence to manufacture MS-21250 fatigue-rated aerospace fasteners, one of very few companies in the world to do so. For engine builders who understand that a fastener is never just a fastener, ARP is the undisputed benchmark.