Product Description:
Hawks Motorsports is pleased to offer our clients the LS1/LS2/LS3/LS6 Crankshaft Harmonic Balancer Bolt, ARP 234-2503. This ARP harmonic balancer bolt is designed for compatible GM LS-series applications and uses an M16 x 2.00 thread, 4.325-inch underhead length and an extra-tall 12-point head. A wide-area 1/4-inch-thick washer is included to distribute clamping load across the harmonic balancer.
When you're building an LS that sees more abuse than a stock daily driver, the crankshaft and balancer aren't the place to gamble on tired hardware. This is one of those details that can get overlooked during an engine build, but the right fastener gives the balancer a solid foundation and makes future service a lot less painful. The tall 12-point head also gives you plenty of socket engagement when you're working that big crank bolt into place.
ARP manufactures this balancer bolt from 8740 chromoly steel and heat treats it for high strength. The bolt features a black oxide finish and is supplied with the required wide-area washer. ARP's current LS-series guide identifies 234-2503 as the harmonic balancer bolt kit for LS-series engines except LS7.
KEY FEATURES
- ARP harmonic balancer/crankshaft bolt
- ARP Part Number: 234-2503
- Designed for compatible GM LS-series engines
- M16 x 2.00 metric thread
- 4.325" underhead length
- Extra-tall 12-point head
- 1-1/16" 12-point socket size
- 8740 chromoly steel construction
- Heat-treated for high strength
- Black oxide finish
- 1/4"-thick wide-area washer included
- Sold individually
- Made in the USA
PRODUCT SPECIFICATIONS
| Specification | Details |
|---|---|
| Manufacturer | ARP |
| Part Number | 234-2503 |
| Product Type | Harmonic Balancer / Crankshaft Bolt |
| Application | GM LS-Series Engines |
| Thread Size | M16 x 2.00 |
| Underhead Length | 4.325" |
| Head Style | Extra-Tall 12-Point |
| Socket Size | 1-1/16" 12-Point |
| Material | 8740 Chromoly Steel |
| Finish | Black Oxide |
| Washer | 1/4" Thick Wide-Area Washer Included |
| Quantity | 1 Bolt |
| Tensile Strength | 200,000 PSI nominal ARP specification |
| UPC | 672036030315 |
| Shipping Weight | 0.40 lb |
| Shipping Dimensions | 9.55" L × 5.80" W × 1.55" H |
ARP's current product information confirms the 4.325" underhead length, M16 x 2.00 thread and washer inclusion. ARP's LS/LT guide identifies the 234-2503 application as LS-series engines except LS7.
VEHICLE FITMENT / FITS THE FOLLOWING MODELS
GM LS-Series Applications
The 234-2503 is designed for compatible GM LS-series applications, including the following engine families:
- LS1 5.7L
- LS2 6.0L
- LS3 6.2L
- LS6 5.7L
The exact application should be confirmed by engine configuration and harmonic balancer/crankshaft requirements rather than vehicle year alone.
Important LS-Series Exclusion
Does not fit LS7 applications.
ARP specifically separates the LS7 harmonic balancer bolt application from 234-2503. ARP's catalog identifies 234-2503 for LS-series engines except LS7, while 234-2504 is the designated LS7/LT1 harmonic balancer bolt kit.
IMPORTANT APPLICATION NOTES AND EXCLUSIONS
- Verify the engine application before ordering.
- 234-2503 is not for LS7 engines.
- The bolt uses an M16 x 2.00 thread.
- Underhead length is 4.325 inches.
- The bolt uses an extra-tall 12-point head.
- A 1/4-inch-thick wide-area washer is included.
- The bolt is sold individually.
- Do not substitute this bolt based solely on the vehicle or model year.
- LS engines can use different harmonic-balancer hardware depending on the specific engine configuration; verify the engine and balancer application before installation.
- For LS7 applications, use the appropriate LS7-specific harmonic balancer bolt rather than 234-2503.
INSTALLATION NOTES
- Verify the crankshaft and harmonic balancer application before installation.
- Confirm the crankshaft threads are clean and undamaged.
- Ensure the harmonic balancer is properly seated before installing the retaining bolt.
- Use the supplied wide-area washer.
- Apply the appropriate lubricant and follow the current ARP installation instructions and applicable GM/engine-builder torque procedure.
- Do not substitute a torque specification from another LS engine without confirming the correct application.
- After installation, verify that the harmonic balancer is fully seated and that there is no interference with the bolt, washer or surrounding components.
FREQUENTLY ASKED QUESTIONS
What is ARP 234-2503?
ARP 234-2503 is an LS-series harmonic balancer/crankshaft bolt kit consisting of one high-strength crankshaft bolt and its wide-area washer.
What LS engines does 234-2503 fit?
The supplied Hawks application identifies the product for LS1, LS2, LS3 and LS6 applications. ARP's broader catalog identifies 234-2503 as the LS-series harmonic balancer bolt kit except LS7.
Does ARP 234-2503 fit an LS7?
No. ARP identifies 234-2503 as the LS-series harmonic balancer bolt kit except LS7. LS7 uses the separate 234-2504 application.
What thread size does the 234-2503 use?
The bolt uses an M16 x 2.00 thread.
How long is the ARP 234-2503 bolt?
The underhead length is 4.325 inches.
What size socket is required?
The extra-tall 12-point head uses a 1-1/16-inch 12-point socket.
Is a washer included?
Yes. The kit includes a 1/4-inch-thick, wide-area washer.
What is the bolt made from?
ARP 234-2503 is manufactured from 8740 chromoly steel and heat treated for high strength.
What finish does the bolt have?
The bolt has a black oxide finish.
How many bolts are included?
The 234-2503 is sold as one harmonic balancer bolt with its washer.
Is 234-2503 reusable?
ARP markets this as a high-strength replacement harmonic balancer bolt rather than a conventional torque-to-yield OEM fastener. However, installation and reuse decisions should follow the current ARP instructions for the specific application.
