When building a high-performance engine, every component must be trusted to handle extreme stress and RPM. The connecting rod bolts are arguably one of the most critical fasteners in your entire build. A failure here is catastrophic, often resulting in a complete engine tear-down. Investing in high-quality rod bolts is not an upgrade; it’s a necessity for any serious performance or racing application.
Automotive Racing Products (ARP) is the industry leader, setting the standard for strength, reliability, and consistency. Their bolts are engineered from premium materials and undergo rigorous testing to ensure they can withstand the immense clamping forces and cyclic loading experienced in a high-output engine. This roundup covers eight of the best ARP rod bolt solutions for a variety of popular engines, from classic small-block Chevys to modern diesel and Coyote powerplants.
Our Recommended ARP Rod Bolt Kits
- ARP 134-6006 Rod Bolt Kit
- ARP 2346301 Gen III LS Series Rod Bolt
- ARP 100-9942 Billet Rod Bolt Stretch Gauge
- ARP Dodge 5.9 Cummins Diesel Rod Bolt Kit
- ARP 230-6301 Rod Bolt Kit
- ARP 2000 Series Rod Bolt Kit for LS Engines
- ARP Custom Age 625+ Rod Bolts for Ford 5.0L Coyote
- ARP 8740 Chrome Moly Rod Bolt Kit for Small Block Chevy
ARP 134-6006 Rod Bolt Kit
This rod bolt kit is a popular choice for builders seeking a reliable upgrade for various applications. Manufactured in the United States, it represents ARP’s commitment to quality control and material integrity. The kit is designed to provide a significant strength increase over stock fasteners, offering greater peace of mind for high-RPM and high-horsepower builds.
The product’s substantial package weight indicates a robust set of components, ensuring you have everything needed for a proper installation. These bolts are engineered for precise fitment and consistent clamping force, which is fundamental for maintaining bearing clearances and overall rod stability under load. Choosing this kit is a straightforward way to enhance the durability of your engine’s bottom end.
ARP 2346301 Gen III LS Series Rod Bolt
Specifically engineered for GM’s Gen III LS series small-block engines with a cracked cap rod design, this kit offers a perfect application-specific solution. The cracked cap design requires fasteners that can handle the unique load characteristics, and ARP has developed these bolts to meet that challenge. They are a direct replacement that provides a substantial upgrade in tensile strength.
Like many top-tier ARP products, these bolts are made in the United States, guaranteeing a high standard of manufacturing. The compact packaging confirms this is a specialized kit with precisely what you need for your LS engine project. Installing these bolts helps ensure your rotating assembly remains secure, which is critical for the performance these engines are known for.
ARP 100-9942 Billet Rod Bolt Stretch Gauge
Proper installation is just as important as the quality of the bolts themselves. This billet rod bolt stretch gauge is an essential tool for any serious engine builder. While torque is often used as a general guide, measuring the actual stretch of the bolt is the most accurate method for achieving the correct preload, which is vital for optimal performance and safety.
This precision tool is machined from billet material in the United States, ensuring durability and accuracy. Its design allows for easy and consistent measurement directly on the rod bolt, helping to prevent under or over-tightening. For anyone using ARP or other high-performance rod bolts, this gauge is a wise investment to guarantee your engine assembly is done correctly.
ARP Dodge 5.9 Cummins Diesel (ACR) Rod Bolt Kit
Diesel engines produce immense cylinder pressures and torque, placing extraordinary stress on the connecting rod bolts. This kit is specifically designed for the legendary 5.9L Cummins engine, providing the necessary strength to handle tuning and increased power levels. The ACR designation points to a specialized material or design tailored for the demands of diesel operation.
Upgrading the rod bolts is one of the most recommended procedures when building a performance Cummins engine. This ARP kit offers a direct fit replacement that significantly improves the margin of safety for the rotating assembly. It is a key component for anyone looking to build a reliable and powerful diesel engine capable of handling modifications.
ARP 230-6301 Rod Bolt Kit
This is a vehicle-specific rod bolt kit designed for the Chevy/GM 6.6L Duramax diesel engine. Duramax engines are known for their performance potential, but unlocking that power requires reinforcing key components. The factory rod bolts can be a weak point under high boost and fuel, making this ARP upgrade a critical step for any build.
The kit is engineered to provide a perfect fit and a massive increase in clamping force over the stock components. This helps prevent rod cap movement and bearing failure, which are common failure points in stressed diesel engines. For Duramax owners aiming for reliability with increased horsepower and torque, this rod bolt kit is an essential foundation.
ARP 2000 Series Rod Bolt Kit for LS Engines
The ARP 2000 Series is a fantastic balance of performance and value, making it a go-to choice for many LS engine builds. These bolts are constructed from a premium chrome moly steel material that undergoes a unique strain-hardening process, resulting in a fastener with a 200,000 psi tensile strength. This provides a strong safety margin for high-revving naturally aspirated and moderately boosted applications.
For the vast majority of street performance and track day LS engines, the 2000 Series offers more than enough strength without stepping up to more expensive alloys. They are a direct replacement for OE-style rod bolts and are known for their consistency and reliability. This kit is an excellent way to build a robust LS engine with confidence.
ARP Custom Age 625+ Rod Bolts for Ford 5.0L Coyote
For builders pushing the limits of Ford’s 5.0L Coyote platform, the Custom Age 625+ rod bolts are the ultimate choice. This material is a step above even the proven ARP 2000, offering exceptional strength and fatigue resistance, which is crucial for engines with high cylinder pressure from forced induction or nitrous oxide.
These bolts are designed to handle the extreme loads encountered in all-out racing applications, providing the highest level of security for your rotating assembly. If you are building a Coyote engine for a supercharged drag racing setup or a high-horsepower road race car, investing in the 625+ material is a wise decision to protect your significant engine investment.
ARP 8740 Chrome Moly Rod Bolt Kit for Small Block Chevy
The 8740 Chrome Moly rod bolt kit is a classic upgrade for the immensely popular small block Chevrolet engine. This material has been a performance standard for decades, offering a significant improvement in strength and durability over original equipment fasteners. It is an excellent choice for street performance engines, classic car restorations, and moderate racing builds.
These kits provide a reliable and cost-effective solution for strengthening the bottom end of your small block Chevy. Whether you are refreshing a high-mileage engine or building a stout street machine, using ARP 8740 rod bolts adds a layer of security and reliability that every builder can appreciate. They are a fundamental part of a solid SBC build.
Buying Guide: How to Choose the Right ARP Rod Bolts for Your Build
When I’m putting together a high-performance engine, the rod bolts are one of the last places I want to cut corners. These small components shoulder a massive responsibility, keeping your connecting rods firmly attached to the crankshaft under immense stress. Choosing the right set is critical for reliability and power. For me, and for many builders, ARP is the go-to brand. But even within their lineup, you need to know what you’re looking for.
The first thing I consider is the material and its corresponding tensile strength. ARP offers several grades, but you’ll most commonly encounter their 8740 chrome molybdenum steel and the higher-end 2000 and 625+ super alloys. For a stout street engine or a moderate turbo build, the standard 8740 bolts are fantastic and have been the bedrock of performance builds for decades. However, when I’m planning a high-RPM, high-horsepower, or forced-induction monster, I step up to the 2000 series or 625+ alloy. These bolts offer a significant increase in tensile and fatigue strength, which translates directly to a larger safety margin. They are more expensive, but the peace of mind is worth it when you’re spinning the engine to 8,000 RPM or making big boost.
Next, you need to think about the installation method. This is a huge one. ARP rod bolts primarily come in two flavors: torque-to-yield (TTY) and torque-plus-angle. Many OEM bolts are TTY, meaning they are stretched to a specific yield point and are designed to be used once. ARP’s philosophy, which I prefer, is to use a precise lubricant and a specific torque value. These bolts are reusable because they are not intentionally torqued into their yield point. You must, and I can’t stress this enough, use the specific ARP lubricant (or their recommended alternative) and follow their torque spec exactly. Using engine oil or a different lubricant will give you an incorrect clamp load, which can lead to a spun bearing or a thrown rod.
Finally, don’t forget about the fit. You can’t just order any ARP bolt and screw it into your rods. Often, the bolt’s body diameter or underhead radius is specific to your rod’s design. Many performance aftermarket rods are sold with ARP bolts already specified and fitted. If you’re upgrading the bolts in a set of factory rods, you need to make sure you’re buying the correct ARP replacement kit. This might require measuring your existing bolts or consulting ARP’s extensive application guide. Getting the right fit ensures proper seating and load distribution. When selecting from the 8 best ARP rod bolts for high-performance builds, matching the bolt to your specific rods and intended use is the final, critical step to a successful and durable engine assembly.
Frequently Asked Questions
Are ARP rod bolts really worth the extra cost over stock bolts?
In my opinion, absolutely. For any build that pushes beyond stock power levels or RPM, they are one of the best investments you can make. Stock bolts are designed to a price point for a stock engine. ARP bolts are manufactured from higher-grade materials, with tighter tolerances and superior heat treatment. This gives you a much larger safety margin against fatigue and failure. A set of rod bolts is far cheaper than repairing an engine after a bolt lets go and windowes your block.
Can I reuse ARP rod bolts, or are they one-time-use like some OEM bolts?
This is a common point of confusion. Most standard OEM torque-to-yield bolts are one-time-use. ARP’s standard fasteners, when installed and torqued correctly with their lubricant, are designed to be reusable. I’ve personally reused them on tear-downs and inspections without issue. However, it’s always a good practice to inspect the bolts for any signs of stretching or thread damage. For an all-out race engine where failure is not an option, some builders prefer to replace them every season for ultimate peace of mind.
Why is the specific lubricant so important when installing ARP bolts?
The lubricant is not a suggestion; it’s a critical part of the torque specification. The torque value you’re trying to achieve is a means to an end—that end is a specific clamp load on the rod cap. Friction plays a huge role in this. If you use a different lubricant, like engine oil, the friction under the bolt head and in the threads changes. This means you could achieve the specified torque value, but the actual clamping force could be significantly higher or lower than intended. Using the ARP lubricant ensures consistent, predictable clamp load across all your bolts.
What’s the difference between the 2000 series and the 625+ super alloy bolts?
Both are top-tier materials for extreme applications, but they have different strengths. The 2000 series is a nickel-chromium-moly alloy that offers an excellent balance of very high tensile strength and good fatigue resistance. The 625+ alloy, made from a material similar to Inconel, is in a class of its own. Its key advantage is its ability to maintain its strength at very high temperatures. This makes it the premier choice for severe applications like turbocharged engines where under-hood and oil temperatures can be extreme, or in nitrous engines with intense cylinder pressure spikes.
Do I need to have my rods resized after installing new ARP bolts?
In almost every case, yes, you should. When you torque a new bolt, especially a higher-strength one like an ARP, it can slightly distort the rod bore. This is because the clamp load is different from the old bolts. To ensure perfect roundness and correct bearing clearance, a machine shop needs to resize the big end of the connecting rod with the new bolts installed and torqued to spec. Skipping this step is a gamble that can lead to premature bearing wear or failure.