ARP 3/8 -24 12pt Rod Bolt - 3AJ1.850-2C

The ARP 3/8-24 12-Point Rod Bolt (Part# 3AJ1.850-2C) is a precision-engineered connecting rod fastener from ARP — one of the most trusted names in high-performance and racing engine hardware. Whether you're rebuilding a street engine or pushing the limits on a race-prepped powerplant, having the right rod bolt is a critical foundation for a reliable, safe bottom end.

Key Features & Benefits

• ARP Quality Engineering: ARP has built its reputation on producing fasteners specifically designed for the demanding stresses of high-performance engines. Choosing ARP rod bolts means choosing hardware engineered with consistent manufacturing tolerances.
• 3/8-24 Thread Specification: The 3/8-24 fine thread pitch is a common standard in performance connecting rod applications, providing reliable clamping force and precise torque control during assembly.
• 12-Point Head Design: The 12-point head allows for accurate torque wrench socket engagement, helping assemblers achieve consistent and repeatable torque values — a must when building a precision engine.
• Individual Bolt Availability: Available as an individual fastener, this bolt is ideal for replacement situations where only one or a small number of rod bolts need to be swapped out, saving you from purchasing a full kit unnecessarily.
• Direct Replacement / Engine Builder Application: Purpose-built for connecting rod use, this bolt is suited for engine builders, machine shops, and DIY enthusiasts performing rod reconditioning or bottom-end assembly work.

Specifications

• Brand: ARP (ARP Fasteners)
• Part Number: 3AJ1.850-2C
• Thread Size: 3/8-24
• Head Style: 12-Point
• Application Type: Connecting Rod Bolt

Fitment

This ARP rod bolt is sold as an individual fastener identified by its thread specification (3/8-24) and head style (12-point) rather than by a specific vehicle make, model, or year. Fitment depends on the connecting rod being used in your engine build — specifically that the rod requires a 3/8-24 threaded rod bolt. This bolt is appropriate for any engine application where a 3/8-24 12-point connecting rod bolt of the appropriate length and grade is required. We strongly recommend confirming your connecting rod's thread specification, bolt length, and required clamping load before ordering. If you have questions about whether this bolt is correct for your specific rods, please reach out to our team before purchasing.

What's in the Box

• 1x ARP 3/8-24 12-Point Connecting Rod Bolt (Part# 3AJ1.850-2C)

Why Buy from ThreePiece.us

At ThreePiece.us, we stock ARP fasteners because engine builders deserve hardware they can trust. We offer free shipping on every order — no minimums, no surprises at checkout. Need to spread out the cost of your engine build? We offer financing through Affirm, so you can get the parts you need now and pay over time. Have a fitment or application question? Our team is here to help you confirm the right bolt before you buy — just reach out and we'll point you in the right direction.

Frequently Asked Questions

Q: How many bolts come in this listing?

A: This listing is for a single (1) ARP 3/8-24 12-point rod bolt, part number 3AJ1.850-2C. If you need bolts for multiple cylinders or a complete set, you will need to order the appropriate quantity.

Q: How do I know if this bolt fits my connecting rods?

A: The key compatibility factors are the thread size (3/8-24), the bolt length required by your specific connecting rods, and the clamping specification your rod manufacturer recommends. We recommend cross-referencing with your rod manufacturer's documentation or contacting ARP directly with your rod specs. Our team at ThreePiece.us is also happy to help — reach out before ordering if you're unsure.

Q: Can I use this bolt on a stock OEM connecting rod?

A: This depends entirely on whether your OEM connecting rod uses a 3/8-24 thread specification. Rod bolt dimensions vary widely by engine family. Confirm your factory rod's thread spec before purchasing.

Q: Is financing available for this order?

A: Yes — ThreePiece.us offers financing through Affirm on eligible orders. You can select Affirm at checkout to review your payment options.