Get Expert Advice
Unlock the full potential of your vehicle with Nemesis UK. Get expert advice from our team including guidance on fitting and recommended installers.
ARP Pro Series head bolt kits are application specific – designed for use with typically competition only components. These fasteners deliver superior strength and meet the ARP “ZERO defect – ZERO failure” quality standard. Hardened and parallel-ground washers are included with each kit to ensure even load distribution and accurate torque readings. All Pro Series head bolts have a reduced wrenching hex or 12-point head and wide area flange to eliminate the need for valve train removal for cylinder head retorquing and permits the use of larger diameter valve springs. Most applications have undercut short bolts that can help eliminate head gasket failures through providing more “stretch” to compensate for the additional compression of gaskets.
*Head Studs vs Bolts*
On many street-driven vehicles, where master cylinders and other items protrude into the engine compartment, it’s probably necessary to use head bolts so that the cylinder heads can be removed with the engine in the car.
For most applications, however, studs are recommended. And for good reason. Using studs will make it much easier to assemble an engine (especially a racing powerplant which must be serviced frequently and quickly!) with the cylinder head and gasket assured of proper alignment.
Studs also provide more accurate and consistent torque loading. Here’s why. When you use bolts to secure the head, the fastener is actually being “twisted” while it’s being torqued to the proper reading. Accordingly, the bolt is reacting to two different forces simultaneously. A stud should be installed in a “relaxed” mode – never crank it in tightly using a jammed nut.
If everything is right, the stud should be installed finger tight. Then, when applying torque to the nut, the stud will stretch only on the vertical axis. Remember, an undercut shorter stud will have a rate similar to a longer, standard shank stud. This provides a more even clamping force on the head. Because the head gasket will compress upon initial torquing, make sure studs and bolts are re-torqued after the engine has been run.
Many parts are held in stock, or available to order for delivery in 10-14 days, subject to availability from our suppliers.
Orders placed before 1pm Monday - Friday may be despatched the same day, provided ALL items in your order are in-stock (exceptions apply).
For orders under £150 or to non-UK destinations, shipping charges are applied at Checkout.
You can check costs for shipping via the Checkout:
Our website pricing usually includes UK VAT.
Once you proceed to Checkout and update your delivery address to a non-UK destination, pricing in the checkout will automatically update to exclude UK VAT.
If you continue to browse our website during this, or subsequent sessions, the pricing you will see in our online store may automatically show as excluding UK VAT due to the delivery address now stored in the Checkout.
IMPORTANT – Orders delivered outside the UK will usually be subject to additional Local Customs and Import Duties. Such charges are the responsibility of the recipient and vary from country to country. Contact your local customs office for more details.
Thanks for subscribing!
This email has been registered!