Use the vehicle search on our site, or check the fitment section on the product page. Fitment is keyed on year, make, engine and displacement — not just the truck model. Send us those four details and the SKU and we will confirm.

<h3 id="three-ways-to-confirm">Three ways to confirm</h3><ol><li><strong>Vehicle search on our site.</strong> Select your year, make, model and engine and the catalogue filters to parts that fit.</li><li><strong>The fitment section on the product page.</strong> Every listing states the exact year range, engine and displacement it covers.</li><li><strong>Ask us.</strong> Email <a href="mailto:support@xotic-performance.com">support@xotic-performance.com</a> (Mon&#x2013;Fri, 9:00 AM &#x2013; 5:00 PM EST).</li></ol><h3 id="what-to-tell-us">What to tell us</h3><ul><li>Year, make and model</li><li>Engine and displacement &#x2014; for example 6.7L Cummins 24V, or 6.6L Duramax LB7</li><li>The <strong>SKU or product link</strong> you are looking at</li><li>Anything non-stock: a swapped engine, a different head, or aftermarket rockers etc.</li><li>Your power target and boost level, if you know them</li></ul><h3 id="watch-the-split-year-ranges">Watch the split year ranges</h3><p>Several diesel platforms changed mid-year. The 5.9L Cummins splits at 1998.5 between the 12-valve and 24-valve, and Ford&apos;s Power Stroke changed at 2003 and again in 2008. If your vehicle sits on a boundary year, check the build date on the door jamb sticker.&#xA0;</p><h3 id="confirm-before-you-install">Confirm before you install</h3><p>Once a fastener is installed and torqued it is considered used and cannot be returned or exchanged. Lay out the kit and check it against the parts list before you start.</p><h3 id="dont-see-your-engine">Don&apos;t see your engine?</h3><p>We produce custom specialty fasteners for rare and unique builds. Tell us what you are working on at <a href="https://www.xotic-performance.com/pages/custom-applications">xotic-performance.com/pages/custom-applications</a>.</p>

How do I confirm a part fits my vehicle?

Every kit ships with instructions including torque values and sequence, and guides are published at xotic-performance.com/pages/install-guides. Lost yours? Email us the SKU for a copy. Always use the specs supplied with your kit.

<h3 id="three-places-to-find-them">Three places to find them</h3><ol><li><strong>In the box.</strong> Every kit ships with an instruction sheet covering torque values, torque sequence and the lubricant to use.</li><li><strong>Our install guides page:</strong> <a href="https://www.xotic-performance.com/pages/install-guides">xotic-performance.com/pages/install-guides</a>.</li><li><strong>From us.</strong> Email <a href="mailto:support@xotic-performance.com">support@xotic-performance.com</a> with your SKU or part number and we will send a copy.</li></ol><h3 id="use-the-specs-that-came-with-your-kit--nothing-else">Use the specs that came with your kit &#x2014; nothing else</h3><p>This is the single most important thing on this page. Torque values are specific to the fastener&apos;s material, thread form, thread finish and the lubricant used. They are <strong>not</strong> transferable:</p><ul><li><strong>Factory service manual values are for factory bolts.</strong> OEM torque-to-yield bolts and performance studs clamp differently and are torqued differently.</li><li><strong>Another brand&apos;s stud specs do not apply.</strong> Different alloys and different lubricants produce a different clamp load at the same torque reading.</li><li><strong>The supplied lubricant is part of the spec.</strong> Substituting engine oil, anti-seize or moly for the assembly lubricant we supply changes the friction coefficient and therefore the actual clamp load, even though the wrench reads the same number.</li></ul><p>Using the wrong torque value is also one of the things that voids warranty coverage &#x2014; over-torquing and incorrect torque sequencing are both explicitly excluded.</p><h3 id="what-to-have-on-hand">What to have on hand</h3><ul><li>A calibrated torque wrench that covers your final value in the middle of its range</li><li>The assembly lubricant supplied with the kit</li><li>A thread chaser to clean the block threads before assembly &#x2014; not a tap, which cuts metal</li><li>Clean rags and a way to remove oil or coolant from blind holes</li></ul><h3 id="still-not-sure">Still not sure?</h3><p>Send us your part number along with your year, make, engine and displacement, and tell us what you are working on. Our team works on these platforms daily and would rather answer the question now than sort out a headgasket later.</p>

Where do I find installation instructions and torque specs for my kit?

Clean and chase the threads, blow out the blind holes, run the studs in hand-tight only, use the supplied assembly lubricant, torque in stages following your kit's sequence, and verify every position at final torque.

<p>General best practices that apply to most head stud installs. <strong>Your kit&apos;s instruction sheet is always the authority</strong> &#x2014; where anything here differs from it, follow the sheet.</p><h3 id="1-prepare-the-block-threads">1. Prepare the block threads</h3><p>Clean, dry threads are most of the job. Run a <strong>thread chaser</strong> &#x2014; not a tap &#x2014; down every hole. A chaser cleans and restores the existing thread form; a tap cuts new metal and can oversize the hole and change your clamp load.</p><p>Blow the holes out completely. Oil or coolant trapped in the bottom of a blind hole is effectively incompressible, and torquing a stud into it can hydro-lock the hole or crack the block. Vacuum or blow out every hole, then check again.</p><h3 id="2-inspect-before-you-assemble">2. Inspect before you assemble</h3><p>Lay the kit out and check it against the parts list. Look over each stud, nut and washer for thread damage, burrs or shipping damage. Do not install any piece you are unsure about &#x2014; email us photos instead.</p><h3 id="3-dry-fit-by-hand">3. Dry-fit by hand</h3><p>Every stud should thread into the block <strong>smoothly by hand, all the way down</strong>. If one binds, stop. Back it out and re-chase that hole. Forcing a binding stud is how threads get pulled.</p><h3 id="4-studs-go-in-hand-tight-only">4. Studs go in hand-tight only</h3><p>Studs are <strong>not</strong> torqued into the block. Run each one down by hand until it seats, then back it off slightly per your instructions. The clamp load is generated at the nut, not at the block end. Torquing the stud into the block preloads the threads wrongly and can distort the deck.</p><h3 id="5-use-the-supplied-assembly-lubricant">5. Use the supplied assembly lubricant</h3><p>Apply it exactly where the instructions say &#x2014; typically under the nut face and on the stud&apos;s upper threads. The lubricant is part of the torque spec: it sets the friction coefficient the value was calculated against. Substituting engine oil, moly or anti-seize changes the real clamp load even though the wrench reads the same number.</p><h3 id="6-torque-in-stages-in-sequence">6. Torque in stages, in sequence</h3><p>Never go straight to final torque. Work up in stages &#x2014; commonly a third, then two thirds, then final &#x2014; and follow your kit&apos;s sequence every pass. The sequence exists to load the deck evenly; skipping it distorts the bore and the gasket seals unevenly.</p><p>Pull each pass in one smooth motion. Jerking the wrench gives a false reading.</p><h3 id="7-verify-every-position-at-final-torque">7. Verify every position at final torque</h3><p>After the final pass, go back around the sequence once more and confirm each nut holds its value without moving. Studs settle slightly as the gasket crushes, and this pass catches the one that did not quite get there.</p><h3 id="8-re-torque-if-your-instructions-call-for-it">8. Re-torque if your instructions call for it</h3><p>Some applications specify a re-torque after an initial heat cycle. Check your instruction sheet &#x2014; if yours calls for one, do it, and follow the same sequence.</p><h3 id="what-voids-your-warranty">What voids your warranty</h3><p>Over-torquing, incorrect torque sequencing, and not following the supplied instructions are all explicitly excluded from warranty coverage, as is engine damage resulting from a fastener failure. Take the extra hour.</p><h3 id="questions-mid-install">Questions mid-install?</h3><p>Email <a href="mailto:support@xotic-performance.com">support@xotic-performance.com</a> (Mon&#x2013;Fri, 9:00 AM &#x2013; 5:00 PM EST) with your part number and what you are seeing.</p>

Head stud installation: best practices for a reliable seal

Cummins, Power Stroke, Duramax, LS, Subaru EJ, Mitsubishi 4B11, Honda/Acura and Nissan VQ, plus thread chasers and tooling that fit any build. Custom fasteners are available for platforms not in the catalogue.

<p>We build high-strength engine fasteners and hard parts, with the deepest coverage on diesel platforms and popular performance gas engines.</p><h3 id="diesel">Diesel</h3><ul><li><strong>Dodge / RAM Cummins 5.9L 12V</strong> &#x2014; 1989&#x2013;1998: head stud kits, head stud &amp; rocker arm combo kits, milled rocker arm pedestal assembly kits</li><li><strong>Dodge / RAM Cummins 5.9L &amp; 6.7L 24V</strong> &#x2014; 1998.5&#x2013;2025: head stud kits</li><li><strong>Ford 7.3L Power Stroke</strong> &#x2014; 1993&#x2013;2002: head stud kits</li><li><strong>Ford 6.0L Power Stroke</strong> &#x2014; 2003&#x2013;2007: head stud kits; 2004.5&#x2013;2010 stand pipe &amp; dummy plug kits</li><li><strong>Ford 6.4L Power Stroke</strong> &#x2014; 2008&#x2013;2010: main stud kits</li><li><strong>Ford 6.7L Power Stroke</strong> &#x2014; 2017&#x2013;2026: turbo intercooler outlet cold side charge pipes</li><li><strong>GM / Chevrolet / GMC 6.6L Duramax</strong> &#x2014; 2001&#x2013;2016, including Hummer: head stud kits</li><li><strong>GM 6.2L &amp; 6.5L</strong> &#x2014; 1982&#x2013;2000: head stud kits</li></ul><h3 id="gas-performance">Gas performance</h3><ul><li><strong>Chevrolet Gen III / IV LS, 4.8L&#x2013;6.2L</strong> &#x2014; 2004&#x2013;2024: head stud kits; rocker arms with bolts and pre-installed trunnion kits for LS1, LS2, LS6, LQ4, LQ9 and LM7; harmonic balancer bolts 1997&#x2013;2015</li><li><strong>Subaru Impreza WRX STi EJ20 2.0L &amp; EJ25 2.5L DOHC</strong> &#x2014; 2002&#x2013;2021: head stud kits</li><li><strong>Mitsubishi 4B11 Evo X 2.0L</strong> &#x2014; 2008&#x2013;2015: head stud kits</li><li><strong>Nissan VQ35 3.5L DOHC</strong> &#x2014; 2002&#x2013;2008: main stud kits</li><li><strong>Honda &amp; Acura 1.2L&#x2013;2.0L 4-cylinder</strong> &#x2014; 1988&#x2013;2023: connecting rod bolts</li></ul><h3 id="universal-tooling-and-hardware">Universal tooling and hardware</h3><ul><li><strong>Thread chasers</strong> &#x2014; metric M6 through M16 and imperial 1/4-20 through 1/2-13, sold individually and in sets</li><li><strong>Assembly lubricant</strong></li><li><strong>12-point nuts and washers</strong> in common sizes</li></ul><h3 id="confirming-your-exact-application">Confirming your exact application</h3><p>Use the vehicle search on our site or check the fitment section on any product page. Several platforms split mid-year &#x2014; the 5.9L Cummins changes at 1998.5, and the Power Stroke changes at 2003 and 2008 &#x2014; so check your build date if you are on a boundary year.</p><h3 id="dont-see-your-engine">Don&apos;t see your engine?</h3><p>We produce custom specialty fasteners for high-performance, rare and unique builds, working directly with you on strength and dimensional requirements. Start at <a href="https://www.xotic-performance.com/pages/custom-applications">xotic-performance.com/pages/custom-applications</a> or email <a href="mailto:support@xotic-performance.com">support@xotic-performance.com</a>.</p>

What engines and platforms do you make parts for?

XOTIC 7200 is our proprietary fastener alloy — 232,000 PSI tensile and 212,000 PSI yield, against 222,000 and 201,000 for 8740 chromoly. Threads are rolled after heat treatment for maximum fatigue strength.

<p><strong>XOTIC 7200</strong> is the alloy our fasteners are made from. It is the reason a XOTIC stud holds more clamp load than a comparable chromoly stud at the same diameter.</p><h3 id="the-numbers">The numbers</h3><table><thead><tr><th><br></th><th>XOTIC 7200 Series</th><th>8740 Chromoly Steel</th></tr></thead><tbody><tr><td>Tensile strength</td><td>232,000 PSI</td><td>180,000 to 210,000 PSI</td></tr><tr><td>Yield strength</td><td>212,000 PSI</td><td>190,000&#x2013;200,000 PSI</td></tr></tbody></table><h3 id="threads-rolled-after-heat-treatment">Threads rolled after heat treatment</h3><p>This detail matters more than the headline numbers. Threads can be cut or rolled, and rolling can happen before or after heat treatment.</p><p>Rolling <em>after</em> heat treatment work-hardens the thread root and leaves compressive residual stress exactly where fatigue cracks want to start. The thread root is the highest-stress region of any fastener &#x2014; it is where studs fail. Rolling after heat treat is more difficult and more expensive to do, and it is what gives our fasteners their fatigue life under the cyclic loading of a boosted engine.</p><h3 id="what-tensile-and-yield-actually-mean-for-your-build">What tensile and yield actually mean for your build</h3><ul><li><strong>Yield strength</strong> is the point where the fastener stretches permanently and stops returning to length. This is the number that governs how much clamp load you can safely apply.</li><li><strong>Tensile strength</strong> is where it finally breaks.</li></ul><p>Higher yield means more usable clamp load for the same stud diameter &#x2014; which is what keeps a head gasket sealed under boost when cylinder pressure is trying to lift the head off the deck.</p><h3 id="rated-operating-range">Rated operating range</h3><p>7200 Series fasteners are engineered for street performance and moderate racing:</p><ul><li><strong>Gasoline:</strong> up to 800 horsepower and 30 psi of boost, with proper tuning</li><li><strong>Diesel:</strong> up to 1,000 horsepower and 60 psi of boost, with proper tuning</li></ul><p>These are also the limits of warranty coverage. If your build targets more than this, contact us about <a href="https://www.xotic-performance.com/pages/custom-applications">custom applications</a> before ordering &#x2014; we would rather spec the right fastener than replace the wrong one.</p>

What is XOTIC 7200 material, and how does it compare to 8740 chromoly?

Studs hold more clamp load, load the block threads more evenly, are reusable, and make head removal easier — the right choice for any boosted or built engine. Bolts are simpler and sometimes the only option in tight chassis.

<p>If you are adding boost, adding power, or have already lifted a head gasket, studs are almost always the answer. Here is why.</p><h3 id="how-they-differ">How they differ</h3><p>A <strong>head bolt</strong> threads into the block and is torqued from the head side. As you torque it, the bolt is being twisted and stretched at the same time &#x2014; some of your torque goes into overcoming thread friction and twisting the fastener rather than into clamp load.</p><p>A <strong>head stud</strong> threads into the block hand-tight first and stays there. The head drops over the studs and a nut is torqued down on top. The stud itself is only ever loaded in tension, never in torsion.</p><h3 id="why-studs-are-stronger-in-practice">Why studs are stronger in practice</h3><ul><li><strong>More accurate, more consistent clamp load.</strong> Removing the twisting component means more of your applied torque becomes actual clamp force, and it is far more repeatable stud to stud.</li><li><strong>Better block thread engagement.</strong> The stud is installed hand-tight into clean threads and stays put, so the block threads are not being loaded and unloaded every time the head comes off.</li><li><strong>Reusable.</strong> Most OEM head bolts are torque-to-yield &#x2014; designed to stretch permanently and be discarded after one use. Studs are not.</li><li><strong>Easier head service.</strong> The head lifts straight up off the studs, and drops back on located by them. Anyone who has fought a heavy diesel head into position without guides appreciates this immediately.</li></ul><h3 id="when-bolts-still-make-sense">When bolts still make sense</h3><ul><li><strong>Tight engine bays.</strong> Studs need vertical clearance to lift the head off. In some chassis you cannot pull the head without removing the engine, which is why some builders stay with bolts on an in-chassis job.</li><li><strong>Stock or near-stock builds</strong> where you are simply replacing a gasket and not raising cylinder pressure.</li></ul><h3 id="whichever-you-choose">Whichever you choose</h3><ul><li>Chase the block threads with a <strong>thread chaser</strong>, not a tap, and blow out every blind hole.</li><li>Use the <strong>assembly lubricant supplied with the kit</strong> &#x2014; it is part of the torque spec.</li><li>Torque in stages, following your kit&apos;s sequence on every pass.</li><li>Never reuse torque-to-yield OEM bolts.</li></ul><h3 id="not-sure-which-is-right-for-your-build">Not sure which is right for your build?</h3><p>Email <a href="mailto:support@xotic-performance.com">support@xotic-performance.com</a> with your year, make, engine, displacement, power target and boost level. We will tell you honestly what your engine needs &#x2014; including when it does not need our most expensive option.</p>

Head studs vs. head bolts: which do I need?

A thread chaser cleans and restores an existing thread without removing metal. A tap cuts new threads — using one in a good block hole oversizes the thread and reduces your clamp load. Always chase, never tap, before a stud install.

<p>This is the most common mistake we see, and it is an expensive one.</p><h3 id="the-difference">The difference</h3><p>A <strong>tap</strong> is a cutting tool. It is designed to create a thread where none exists, and it removes metal every time it goes in.</p><p>A <strong>thread chaser</strong> is a cleaning and restoration tool. It follows the existing thread form and pushes debris, carbon, old sealant, rust and thread locker out of the way without cutting the parent metal.</p><h3 id="why-it-matters-on-a-head-stud-install">Why it matters on a head stud install</h3><p>Running a tap down a perfectly good block hole slightly oversizes the thread. Thread engagement drops, the fit loosens, and the clamp load your carefully calculated torque spec was supposed to produce is no longer what you actually get. On an aluminium block or head the effect is worse.</p><p>Meanwhile, the actual problem &#x2014; carbon, oil film, coolant residue, old sealant in the bottom of a blind hole &#x2014; is exactly what a chaser is designed to remove.</p><h3 id="how-to-use-one">How to use one</h3><ol><li>Run the chaser down each hole by hand, backing it out periodically to clear debris.</li><li>Blow the hole out completely with compressed air. Wear eye protection &#x2014; this launches a surprising amount of material.</li><li>Vacuum or swab any remaining fluid from blind holes. Trapped oil or coolant is effectively incompressible and can hydro-lock a hole or crack a block when a stud is run down into it.</li><li>Dry-fit each stud by hand. Every one should thread in smoothly all the way. If one binds, back it out and chase that hole again.</li></ol><h3 id="our-thread-chasers">Our thread chasers</h3><p>We make chasers in metric sizes from <strong>M6 through M16</strong> and imperial sizes from <strong>1/4-20 through 1/2-13</strong>, available individually and in multi-piece sets. They are not engine-specific &#x2014; any chaser of the right size and pitch works on any build, so they earn their place in the toolbox permanently.</p><h3 id="which-size-do-i-need">Which size do I need?</h3><p>Email <a href="mailto:support@xotic-performance.com">support@xotic-performance.com</a> with your year, make, engine and displacement, or the part number of the fastener kit you are installing, and we will tell you exactly which chaser matches.</p>

What is a thread chaser, and why shouldn't I use a tap?

The quickest way to reach a person — good for fitment checks, torque questions and order status. If we're offline, leave your message and we'll pick it up the next business day.

Send us a message and we'll reply within 1–2 business days.

Speak with our support team Monday–Friday, 9 AM–5 PM EST.

Find An Installer

Shop

Install Guides

Returns

Warranty

Xotic Performance

Fitment, XOTIC 7200 material, head studs vs. head bolts, thread chasers, torque specs and installation best practice.

Products & Technical