We sell ARP Head Studs in kits that include: the appropriate amount of head studs, parallel ground washers, and 12 point nuts for your engine, as well as ARP assembly lube and torque specifications.
ARP Head Studs are known across all types of motorsports as the undisputed best. ARP manufactures fasteners used in almost every popular motorsport, including NASCAR, IRL, Formula 1, Top Fuel, and Pro Stock. With over 40 years of industry experience there is no doubt that they have earned the title of "World leader in Fastener Technology".
High performance engines are only as strong as their weakest link. OEM head bolts are generally designed for a limited range of performance. When used in high performance applications, (especially if forced induction and nitrous are used) OEM head bolts can be pushed beyond their limits and stretch or fail. If a head bolt fails, usually the head gasket will need to be replaced at the very least and sometimes greater damage may occur.
Most OEM head bolts are designed to stretch during engine assembly and as a result should never be re-used. This means that if you are removing your cylinder head to replace a head gasket or perform and engine overhaul you should always buy new fasteners. Upgrading to ARP head studs is a great idea for a number of reasons. The ARP studs are manufactured using much tighter tolerances and grades of material. When installed and torqued properly, ARP head studs can provide much higher clamping force than OEM bolts or studs. As an example; a standard grade 8 high quality steel bolt has an approximate tensile strength of 150,000 PSI. While this may sound like a very strong bolt, (grade 8 bolts are in fact very strong) most ARP head studs use a special grade of alloy steel with a tensile strength of 200,000 PSI or greater!
If you are replacing a head gasket or performing an engine overhaul (for turbo, supercharged or nitrous use) we highly recommend replacing your head bolts with ARP head studs. With a high quality gasket (We recommend using a Cometic head gasket) and a clean mating surface you can virtually eliminate future issues. As a result you can experience less, gasket failures, overheating and compression issues and more power!
Most ARP head studs are made from 200,000 PSI tensile strength special alloy steel (superior to aircraft grade). Some head stud kits use "ARP 2000" grade material (220,000 PSI tensile strength) or "Custom Age 625" grade material (260,000 to 280,000 PSI tensile strength!).
Installation Tip: Since most gaskets compress during initial installation, you should make sure to re-torque your studs after the engine has been run. Always follow the included ARP instructions during install for best results.