Written by Bill Holland
Automotive Racing Products, Inc. – better known as simply “ARP” – can trace its roots back to 1968 when company founder Gary Holzapfel, who was then employed by an aerospace fastener manufacturer, sought to help some of his drag racer friends, Don Prudhomme among them, overcome their fastener-related engine reliability issues. The demand for premium grade head studs, and other fasteners, fueled the fledgling company’s growth, which has necessitated expanding from its original backyard garage operation to a current footprint with some 200,000 square feet under-roof in multiple facilities for R&D, manufacturing, QC, warehousing, and administrative operations.
[Editor’s Note: This story originally appeared in DI #191, the 30 Under 30 Issue, in November / December of 2024.]
ARP remains a family-owned and operated business, with three generations (founder Gary, his son, Mike – the company president – and grandson Ryan) involved. The company’s goal is to make the best possible products and proudly does everything in-house at its Southern California facilities – from forging and heat-treating to precision machining, packaging, and distribution.
As an interesting aside, Gary’s dad was a chef and instilled a love of fine food in his family. With a scarcity of good places to eat in the area, the company built a restaurant at the hub of ARP’s manufacturing operations in Santa Paula. It’s called “Hozy’s Grill” (the nickname bestowed upon the chef) and it’s open to the general public. It’s decorated in a racing theme, staffed by classically trained chefs, imports the highest quality meats, poultry, fish, and vegetables, and even carries an impressive “2 Glass” rating from the prestigious Wine Spectator. It’s well worth checking out at www.HozysGrill.com.
From a drag racing standpoint, the motto of the long-time NHRA major sponsor (and sponsor off the newly-announced “6-Second Club” for Factory X competitors) is “Working together, we win races.” As such, the company has developed strong working relationships with many of the sport’s leading competitors, crew chiefs, and engine builders. ARP’s in-house testing capabilities (which rival that of major Detroit automakers) are employed to develop new fasteners to solve issues that racers are having.
The company also provides free torque wrench testing services at NHRA national events. Over the years they have seen many competitors come with torque wrenches that were off by as much as 30-40% or more. Since the effectiveness of a fastener depends on it being properly preloaded, ARP urges racers to make sure their torque wrenches are properly calibrated.
Another potential problem lies in how the fastener is lubricated, as inconsistencies in the lubricant itself can lead to a condition known as “preload scatter.” That’s why the company invested considerable effort and resources to develop ARP Ultra-Torque Fastener Lubricant
. It’s far superior to oil, moly, EPL, in consistency and laboratory-proven to deliver 95-100% of the desired preload on the first, and all subsequent pulls on the torque wrench.
It’s important to understand that the metal used in manufacturing fasteners comes in four grades: commercial, aircraft, CHQ, and SDF (seamless, defect free). ARP employs only the two best – which are far superior to “aircraft” quality. Another metallurgical factor of importance is the alloy. For critical engine fasteners, like head and main studs/bolts and connecting rod bolts, ARP uses five types of alloys (8740 chrome moly, ARP2000, Custom Age 625+, L19, and ARP 3.5) which range from a 200,000 psi nominal tensile strength to 280,000 psi. Accordingly, you can get fasteners suited for applications that range from a normally aspirated gas-burning engine to a supercharged nitro-guzzler.
There is also much to be said on how a fastener is manufactured. ARP does its own heat-treating in-house, with studs placed in racks – not thrown into a bin – to assure accurate through-hardening. Threads are rolled (not cut) after heat-treating to provide vastly superior fatigue strength and meet AS8879D specifications to ensure the best possible thread engagement. All operations are the best possible – not the cheapest.
Over the years ARP has developed some 5,500-plus fastener kits that cover everything from an old flathead Ford to the latest Chevy LS/LT, Ford Coyote and Godzilla, and Chrysler Gen III Hemi applications. The company manufactures a wide variety of accessory bolts and studs that are made from polished stainless steel or black oxide finished 8740 chrome moly. Both are nominally rated at 180,000 psi tensile strength – fully 20% stronger than Grade 8 hardware.
For additional information, visit www.ARP-bolts.com. A free copy of the latest catalog – which includes over three dozen pages of valuable tech information – is available upon request. Personalized tech assistance can be obtained by calling 800-826-3045.
This story was originally published on December 27, 2024. 
The post Partner Profile: A Look at Automotive Racing Products Inc. first appeared on Drag Illustrated.