Want engine main studs and bolts that actually hold up? Choose proven kits like ARP for LS/SBC or Speedmaster for BBC/350, built from chromoly or 8740 steel with hardened washers and Grade 10.9–12.9 strength.
Match thread pitch, stud length, and main cap pattern, chase threads, and use proper lubricant for accurate preload.
Use parallel-ground washers and 12-point or hex nuts as space allows, and confirm fit with windage trays.
| ARP Main Stud Kit for GM LS-Series (Dart LS Next) |
| Professional Grade | Fastener Type: Stud | Nuts Included: 12-point nuts included | Application Area: Engine main (mains) for GM LS / Dart LS Next | VIEW LATEST PRICE | Read Our Analysis |
| Speedmaster PCE287.1002 Main Stud Kit |
| Race-Ready Strength | Fastener Type: Stud | Nuts Included: 12-point nuts included | Application Area: Engine main (4-bolt SBC 350) | VIEW LATEST PRICE | Read Our Analysis |
| Speedmaster Main Stud Kit for Chevy BBC 454 |
| Heavy-Duty Performer | Fastener Type: Stud | Nuts Included: 12-point nuts included | Application Area: Engine main (BBC 454) | VIEW LATEST PRICE | Read Our Analysis |
| ARP 1345601 4-Bolt Main Stud |
| Trusted Classic | Fastener Type: Main stud kit (stud) | Nuts Included: Hex/12-point nuts included (kit) | Application Area: Engine main (Small Block Chevy) | VIEW LATEST PRICE | Read Our Analysis |
| ARP 134-5402 Main Stud Kit for Small Block Chevy |
| Small-Block Specialist | Fastener Type: Main stud kit (stud) | Nuts Included: Hex nuts included | Application Area: Engine main (Small Block Chevy) | VIEW LATEST PRICE | Read Our Analysis |
More Details on Our Top Picks
ARP Main Stud Kit for GM LS-Series (Dart LS Next)
Should you’re building or upgrading a Dart LS Next or GM LS-series engine and want strong, reliable main retention that won’t let you down under power, the ARP Main Stud Kit is a top choice. You’ll get chromoly alloy studs with a black oxide finish, 7/16-20 UNF threads, and 12-point flat nuts made for 4-bolt mains. You can count on ARP part 134-5901 to fit LS-series blocks and Dart LS Next decks. The kit weighs about 4.19 pounds, ships in compact packaging, and carries manufacturer warranty support. Install them carefully and torque to spec for lasting confidence.
- Fastener Type:Stud
- Nuts Included:12-point nuts included
- Application Area:Engine main (mains) for GM LS / Dart LS Next
- High‑strength Alloy:Chromoly alloy steel
- Washer(s) or Washer Provision:Designed for 4‑bolt mains with nuts (washer/provision implied)
- Return/Warranty Support:Manufacturer warranty available; Amazon 30‑day return noted
- Additional Feature:12-point nut heads
- Additional Feature:Black oxide finish
- Additional Feature:Dart LS Next fitment
Speedmaster PCE287.1002 Main Stud Kit
Provided you’re building or rebuilding a Small Block Chevy 350 with 4-bolt mains and want race-ready reliability, the Speedmaster PCE287.1002 Main Stud Kit is made for you. You’ll like its 8740 chromoly alloy studs that offer aircraft-quality strength and consistent torque readings after heat treatment, grinding, and thread-rolling. The kit gives you parallel-ground 4130 washers and high-strength 12-point nuts in 7/16 or 1/2 UNC sizes, rated Grade 10.9 for demanding use. You’ll feel confident with studs that meet high tensile and shear specs, easy fitment to 4-bolt mains, and clear manufacturer notices and return policy.
- Fastener Type:Stud
- Nuts Included:12-point nuts included
- Application Area:Engine main (4-bolt SBC 350)
- High‑strength Alloy:8740 chromoly alloy steel
- Washer(s) or Washer Provision:Includes parallel‑ground 4130 washers
- Return/Warranty Support:Manufacturer warranty available; vendor 30‑day return policy noted
- Additional Feature:8740 chromoly studs
- Additional Feature:Parallel-ground 4130 washers
- Additional Feature:Race-quality torque consistency
Speedmaster Main Stud Kit for Chevy BBC 454
Should you’re rebuilding or upgrading a Chevy BBC 454 and want rock-solid main cap fastening, the Speedmaster PCE287.1003 main stud kit is a smart choice for hands-on enthusiasts and weekend racers who value strength and simplicity. You get a complete kit with studs, 12-point nuts, and washers designed for 2-bolt mains. The fasteners boast 190,000 psi yield strength, so you can trust them under stress. They fit BBC 454 blocks but don’t work with windage trays. The kit weighs 2.67 pounds and ships in compact packaging. It carries a 12-month limited warranty and a 30-day retailer return option.
- Fastener Type:Stud
- Nuts Included:12-point nuts included
- Application Area:Engine main (BBC 454)
- High‑strength Alloy:High‑strength alloy (rated 190,000 psi)
- Washer(s) or Washer Provision:Washers included
- Return/Warranty Support:12‑month limited warranty; vendor 30‑day return noted
- Additional Feature:Chevy BBC 454 specific
- Additional Feature:2-bolt main configuration
- Additional Feature:12-month limited warranty
ARP 1345601 4-Bolt Main Stud
Should you’re building or upgrading a small block Chevy and want rock-solid crank support, the ARP 1345601 4-Bolt Main Stud kit is made for you. You’ll like that ARP uses alloy steel with a painted finish and Grade 10.9 hardness, so the studs handle serious stress. They come as an M12 x 1.75 metric set with flat hex heads that fit common tools. Made in USA, the kit weighs about 3.26 pounds and ships in compact packaging. Reviews show strong user trust. You can expect reliable fit for SB Chevy mains and warranty support from ARP as required.
- Fastener Type:Main stud kit (stud)
- Nuts Included:Hex/12-point nuts included (kit)
- Application Area:Engine main (Small Block Chevy)
- High‑strength Alloy:Alloy steel (high grade)
- Washer(s) or Washer Provision:Kit includes necessary hardware (washers implied)
- Return/Warranty Support:Manufacturer warranty available; Amazon 30‑day return noted
- Additional Feature:Metric M12 x 1.75
- Additional Feature:Made in USA
- Additional Feature:Painted exterior finish
ARP 134-5402 Main Stud Kit for Small Block Chevy
In case you’re building or rebuilding a small block Chevy with two-bolt mains, the ARP 134-5402 main stud kit is a smart choice because it gives you strong, reliable fasteners made from chromoly alloy steel that stand up to high stress. You’ll get 7/16 inch UNC studs and hex washer nuts finished in black oxide for corrosion resistance. They fit small journal, two-bolt main blocks and feel precise in your hands. Made in the USA, these premium studs add durability and confidence during assembly. You’ll appreciate the fit, the weight, and the peace of mind they bring.
- Fastener Type:Main stud kit (stud)
- Nuts Included:Hex nuts included
- Application Area:Engine main (Small Block Chevy)
- High‑strength Alloy:Chromoly alloy steel
- Washer(s) or Washer Provision:Kit includes nuts (washer provision implied)
- Return/Warranty Support:Manufacturer warranty available; Amazon 30‑day return noted
- Additional Feature:Small-journal SBC fitment
- Additional Feature:7/16″ UNC thread
- Additional Feature:Made in USA
Factors to Consider When Choosing Engine Main Bolts Studs
At the moment you pick main bolts or studs, consider initially about material strength and whether the part can handle your engine’s power and heat. Check thread size and head style so the fit is exact and the wrench turns cleanly, and don’t forget that good washers and nuts affect clamp load and reliability. Also pay attention to the bolt’s torque and stretch limits because those numbers tell you how to tighten safely and avoid costly engine damage.
Bolt Material Strength
Because your engine’s main studs take repeated hits from cylinder pressure and vibration, you need bolts that won’t bend, crack, or let you down. You should look initially at tensile and yield strength, since they tell you how much load a stud can take before it deforms or breaks. High strength alloy studs often reach about 190,000 to 200,000 psi. Next, consider material grade like chromoly 8740 or equivalent grade 10.9 or 12.9, because heat treatment and toughness improve fatigue resistance under cycling loads. Fatigue strength and notch sensitivity matter most for repeated bending and torsion. Also check thread rolling and surface coatings for fewer stress risers and consistent torque. Finally, balance hardness with ductility so studs are strong but not brittle.
Thread Size Fitment
In case you’re swapping or upgrading main bolts and studs, matching thread size and fit is one of the initial choices that will make or break the job. You must match diameter and pitch exactly to the block and main cap holes. Common sizes like 7/16-20 UNF, 7/16-14 UNC, 1/2-13 UNC, and M12×1.75 matter because wrong pitch strips threads or gives bad torque readings. Also check thread class and form so clearance fits as intended. Measure stud or bolt length so threads fully engage the tapped depth, aiming for at least 1.5 times the diameter in steel. Verify handedness and any dowel or interference features. In the event threads are damaged, chase them or use helicoil inserts instead of changing sizes.
Head Style Preference
You matched the threads and lengths, so now pick a head style that fits your build and the tools you’ll use. Consider about access and torque initially. Provided you work in tight manifolds, 12-point nuts let you swing less and apply higher torque without hunting for clearance. Should you prefer common sockets and easy sourcing, hex heads are simple and familiar, though they need more room to turn. For soft or thin cap material, choose flat or washer-style heads so the load spreads and parts don’t cave in. Low-profile heads help where external space is tight, but they trade off clamping surface and thread engagement. Also match head style to how you torque bolts, since some styles give steadier wrench readings and repeatable results whenever you need precision.
Washer And Nut Quality
Usually you’ll discover that washers and nuts do more work than people expect, so pick them with care and intent. You want hardened, parallel-ground washers made from heat-treated alloy steel so they spread the clamping load and resist crushing as you crank torque up. Match those washers to 12-point or high-quality hex nuts rated to at least Grade 10.9 or ASTM A193 B7 equivalent. Also make sure nut and washer materials and finishes pair alongside the stud to avoid galvanic corrosion and keep torque readings steady. Controlled nut geometry matters too; accurate thread class and chamfers give you uniform preload and repeatable torque to tension behavior. Before assembly, inspect washer flatness and nut threads because damage can cut clamp load by 10 to 30 percent.
Torque And Stretch Limits
You’ve picked good washers and nuts, and now it’s time to focus on how tight those fasteners should be and how much they’ll stretch as you torque them. You’ll get clamp load right upon following builder or manufacturer torque specs. Those specs aim to give correct preload without pushing the stud past yield. For example, many 7/16-20 UNF high-strength studs use torques around 60 to 110 ft-lb depending on lubricant and grade. Stretch is more reliable than torque alone, so high-quality studs are often tightened to a set micrometer elongation, like 0.006 to 0.015 inches. Use the proper thread lubricant because it changes torque-to-clamp by 15 to 40 percent. For race or critical engines, use calibrated torque wrenches and a stretch gauge or mark-and-measure checks to make certain even preload and avoid failure.
Finish And Corrosion Resistance
Whenever parts sit in a damp garage or face road salt, the finish on your main bolts and studs matters more than you might reckon. You want a finish that keeps rust at bay and lets torque turn into the right clamp. Black oxide helps reduce glare and gives basic protection, but you’ll need anti-seize or a coating should moisture’s present. Zinc and zinc-nickel plating work well in humid or salted conditions, and zinc-nickel lasts longer in salt tests. Cadmium resists corrosion and lubricates nicely, yet rules and health concerns push you toward zinc-nickel alternatives. Stainless fasteners resist corrosion naturally, though some grades lose strength compared with high-strength alloy studs. Keep in mind finishes change thread friction, so follow finish-specific torque or lubrication to get correct preload.
Compatibility With Blocks
Upon selecting main bolts or studs, the initial thing to check is whether they physically fit the block, because a wrong thread, length, or shoulder will cause headaches you don’t want. You should verify thread size, pitch and class match the block so threads engage cleanly and you avoid cross-threading. Then confirm stud length and shoulder dimensions so mains, caps, crank and oil passages have proper clearance. Also make sure the stud pattern matches the block and cap design, whether two bolt, four bolt, studs or bolts. Check full versus partial thread and pick material and heat treatment rated for the torque and load you’ll apply. Finally match finish and corrosion properties to sealing practices and any coatings or threadlocker you plan to use.
Manufacturer Warranty Coverage
How much protection do you really get from a manufacturer’s warranty on main bolts or studs, and what do you need to prove in the event something goes wrong? You should initially check length and scope. Look for coverage of material defects, manufacturing faults, and failure under specified torque or load. Then confirm limits like time, mileage, and exclusions for race or high performance use. Also see whether proper installation proof is required, such as torque specs, installer certification, or documented procedures, because improper installation can void coverage. Review claim steps and needed paperwork like receipts, photos, and return authorizations, and whether the maker pays shipping or inspection. Finally, observe remedies, pro rated terms, and whether third party changes cancel the warranty.
