Classic Inlines
603 W Pecos Ave
Mesa, AZ 85210

ARP Studs & Bolts

ARP® studs and bolts are substantially stronger than OEM fasteners. It is important to note that ARP ® heat-treats the bolts using special vertical racks to ensure complete 360 ° penetration, and rolls the threads after heat-treating. This procedure accounts for a fatigue strength approximately ten times greater than fasteners, which are threaded prior to heat-treating.

Click here to see all of the ARP Products that we stock.

Studs verses Bolts

For most engine rebuilds we recommend using ARP studs, and for good reason. Studs make it much easier to assemble an engine, as well as insuring proper alignment of the cylinder head and the head gasket. Studs also prevent erroneous torque readings, and provide more accurate and consistent torque loading, which aids in preventing head gasket failures. Here's why.

When you use bolts to secure the cylinder head, or main caps, the fastener is actually being " twisted " while it is being torque'd to the proper reading. Accordingly, the bolt is reacting to different forces simultaneously. ARP Studs should be installed in a relaxed mode, never cranking them in tightly using a jammed nut. If everything is right, the stud should be installed finger tight only. Then when applying torque to the nut, the stud will stretch only on the vertical axis. This provides even more clamping force on the head, and/or main caps.

When an engine is rebuilt, more often than not, the block is decked and the cylinder head milled. This removes material from the top of the block and the bottom of the cylinder head, to true up the mating surfaces for a good seal. This is also done to increase the compression ratio. Depending on the amount of material removed, the head bolts could bottom out during installation, giving the installer false torque readings. This is completely eliminated by using studs, thus assuring that the cylinder head was installed properly.

Remember to make sure all bolts and studs are re-torque'd after the engine has been run for a few minutes.

Recommended ARP Torque Specs
Engine Size
Rod Bolts
19-24 lbs
19-24 lbs
21-26 lbs
Main Stud
65-75 lbs
60-70 lbs
60-70 lbs
Head Stud
70-75 lbs
70-75 lbs
70-75 lbs

Six Simple Tips

If you can't  easily screw a nut and bolt together by hand they shouldn't  be used.

When you use a locking chemical for studs, bolts or even nuts, consider if you really need it.

If you are using a locking chemical, don't  force nuts off or studs out without a proper first step, like heat or release chemical.

Get access to a master gauge to check your torque wrenches. You'd  be surprised at how many torque wrenches read incorrect.

Don't  forget that you'll  get different torque readings when using different lubricants.

Use ARP's moly lube whenever possible.

How to Install Studs

Clean and chase all bolt threads in block to ensure proper thread engagement and accurate torque readings.

All hardware and holes should be clean, dry, and inspected for damage prior to installation of the studs.

Lubricate the washer and nut with oil or ARP moly lubricant prior to installation.  

Coat the stud threads with ARP thread sealer if the stud extends into a water jacket, then screw the stud in hand tight only.

Following the engine manufacturers torque pattern, torque each nut three times to the recommended specs. Torque instructions are included in each kit.

For more information visit ARP's Home Page

NOTE: If a permanent mounting is preferred, Loc-Tite or a high temperature RTV silicon may be used. What ever product is used, it is imperative  that the stud is torque'd to the proper level before the sealant has cured.

Click here to see all of the ARP Products that we stock.

CAUTION: When installing cylinder head studs on the small Ford inline six, you need to make sure the front stud, on the exhaust side of the motor, doesn't project deep enough so as to interfere with the water pump impeller. Verify before starting your motor, or the water pump impeller may be damaged, possibly resulting in total engine failure. If this occurs, simply remove the stud and grind off approximately one quarter of an inch. This is also the only wet stud (having contact with the engine coolant, therefore you must use ARP thread sealer (or equivalent) to prevent leakage, or rust which may make stud removal difficult.

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