1. Engine Crankshafts Products
  2. sku: 20335969133739603
  3. POWERBOND DAYCO SX-3487

POWERBOND BY DAYCO SX-3487 Engine Harmonic Balancer Iu 5.7L V8

fits model: C1500, Suburban. make: Gmc. year: 1969–1974.

Sx-3487 Powerbond By Dayco Engine Harmonic Balancer For 1969-1974 Gmc C15 C1500 Suburban 5.7l V8 Iu

( Brand: Powerbond By Dayco ), ( Manufacturer Part Number: SX-3487 ), ( Item Weight: 11.1100 ), ( Ipn: C254 17-42 ), ( Placement On Vehicle: Engine Cylinder Block ), ( Compatible Model: C15/c1500 Suburban ), ( Compatible Year: 1974 1973 1972 1971 1970 1969 ), ( Core Charge: Free No Core Charge ), ( Type: Engine Harmonic Balancer ), ( Fitment Type: Direct Replacement ), ( Bundle Description: 1 Pc Genuine Dayco Engine Harmonic Balancer ), ( Timing Marks: Yes ), ( Overall Width: 2.343 In / 59.50 Mm ), ( Hardware Included: No ), ( Ring Width: 1.319 In / 33.48 Mm ), ( Counterweight Balance: Neutral, No Counterweight ), ( Outer Ring Material: Grey Iron ), ( Overall Outside Diameter: 7.993 In / 203.00 Mm ), ( Nose Outside Diameter: 1.763 In / 44.78 Mm ), ( Crank Bore: 1.245 In / 31.60 Mm )

Review POWERBOND BY DAYCO Engine Harmonic Balancer Gmc C15 5.7l V8 Iu fits SUBURBAN C1500 1969–1974

The **Powerbond Dayco SX-3487 Engine Harmonic Balancer** is a high-performance, precision-engineered replacement part designed specifically for the iconic 1969 through 1974 General Motors C15 and C1500 Suburban models equipped with the legendary **5.7L (350 cubic inch) IU (Inline Underdrive) V8 engine**. This balancer is a critical component in maintaining smooth engine operation, dampening the torsional vibrations generated by the crankshaft s rotational forces to prevent excessive wear on the drivetrain, engine mounts, and related components. Crafted from **high-strength steel**, the SX-3487 features a **robust, machined surface** that ensures optimal balance and durability, reducing the risk of catastrophic failure such as a cracked or shattered balancer that can lead to costly engine damage or transmission issues. Unlike standard OEM parts, this aftermarket harmonic balancer incorporates **enhanced rubber damping material** within its internal design, providing superior vibration suppression and a quieter, more refined power delivery, particularly noticeable under heavy throttle conditions or at higher RPMs. The **precision-fit pulley** is engineered to align perfectly with the crankshaft, ensuring seamless installation and minimizing the chance of wobble or misalignment, which can exacerbate drivetrain stress. Whether you're restoring a classic C15 Suburban for weekend cruising or modifying your truck for increased horsepower, the Powerbond Dayco SX-3487 is a **reliable, long-lasting upgrade** that enhances both performance and longevity. Built to exceed factory specifications, this balancer is a trusted choice among mechanics and enthusiasts alike, offering peace of mind with every start-up.

**Pros and Cons of Buying a Powerbond Dayco SX-3487 Engine Harmonic Balancer for a 1969 1974 GMC C15/C1500 Suburban (5.7L V8 IU)**

### **Pros**

1. **Compatibility and Fitment**

The SX-3487 is specifically designed for the 5.7L (350 CID) small-block Chevrolet V8 engines, including the IU (Intake Under) variant used in your GMC C15/C1500 Suburban. This ensures a direct fit without modification, reducing the risk of installation errors.

2. **Durability and Performance**

Powerbond and Dayco are well-regarded brands for harmonic balancers, known for using high-quality materials like steel and rubber compounds that resist cracking, warping, and premature wear. A properly functioning balancer helps dampen engine vibrations, improving drivability and reducing stress on the crankshaft and related components.

3. **Compatibility with Aftermarket Upgrades**

If you ve modified your engine (e.g., forced induction, high-performance camshafts, or heavy-duty components), a high-quality balancer like this one can help mitigate the increased stress on the crankshaft assembly. It s a common upgrade for performance builds.

4. **Ease of Installation**

The SX-3487 is a direct replacement part, meaning it should bolt on without requiring machining or customization. This makes it a straightforward DIY-friendly upgrade, especially if you re comfortable with basic engine work.

5. **Preventative Maintenance**

Harmonic balancers wear out over time due to heat, vibration, and rubber degradation. Replacing it as a preventative measure can avoid sudden failure, which could lead to severe engine damage (e.g., bent crankshaft or damaged timing components in interference engines). Since your Suburban is a classic, this is particularly important for longevity.

6. **Cost-Effective Upgrade**

Compared to the potential cost of repairing crankshaft damage or replacing a failed balancer mid-journey, purchasing a new one upfront is a cost-effective choice. Prices are reasonable for a quality part, especially when sourced from reputable suppliers.

7. **Reduced Noise and Smoothness**

A worn balancer can cause rattling, whining, or excessive vibration. Replacing it with a new SX-3487 should eliminate these issues, resulting in a smoother-running engine.

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### **Cons**

1. **Potential for Counterfeit Parts**

The aftermarket for classic GM parts can be flooded with counterfeit or low-quality replicas, especially for older models. Ensure you purchase from a trusted seller (e.g., RockAuto, Summit Racing, or a reputable local parts store) to avoid receiving a substandard or mislabeled balancer. Verify the part number and inspect the packaging for authenticity.

2. **Installation Challenges**

While the SX-3487 is a direct replacement, removing the old balancer may require careful handling to avoid damaging the crankshaft pulley or the crankshaft itself. If the old balancer is seized or corroded, you may need to use heat or penetrating oil to loosen it, which could be time-consuming.

3. **Limited Longevity with Heavy Use**

Even high-quality balancers have a finite lifespan, especially under extreme conditions (e.g., high RPMs, aggressive driving, or extreme temperatures). If you plan to use the vehicle for high-performance applications (e.g., drag racing or frequent high-speed driving), the balancer may need replacement more frequently than in a daily driver scenario.

4. **Cost of Associated Labor**

If you re not comfortable performing the installation yourself, labor costs at a shop can add up, particularly for a classic vehicle where mechanics may charge premium rates. Factor this into your budget if outsourcing the work.

5. **Risk of Improper Alignment**

Misalignment during installation (e.g., not centering the balancer properly on the crankshaft) can cause premature wear or failure. This requires attention to detail and possibly the use of alignment tools or a dial indicator to ensure proper fitment.

6. **Limited Availability of OEM Parts for Reference**

Since OEM balancers for these older GM engines are no longer produced, you may lack a direct comparison for quality. However, the SX-3487 is widely recommended by enthusiasts and mechanics as a reliable alternative.

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### **Conclusion and Recommendation**

The **Powerbond Dayco SX-3487 harmonic balancer** is a **strong, well-supported choice** for your 1969 1974 GMC C15/C1500 Suburban with a 5.7L V8 IU engine. Its **direct fitment, durability, and compatibility with both stock and modified engines** make it a practical upgrade for improving drivability and preventing catastrophic failure. The **cost is justified** by the part s role in protecting your engine s longevity, especially given the potential expense of crankshaft damage from a failed balancer.

**Recommendation:**

- **Proceed with purchasing the SX-3487** from a reputable seller to ensure authenticity.

- **Inspect the old balancer** for signs of wear (cracks, separation, or rubber degradation) before installation. If it s already failing, replace it immediately.

- **Follow installation guidelines carefully**, ensuring the balancer is properly aligned and securely bolted. Use a torque wrench to tighten the bolts to the manufacturer s specifications (typically around 40 60 ft-lbs, depending on the source).

- **Consider pairing this upgrade with other preventative maintenance**, such as checking the crankshaft pulley and timing components, to maximize the health of your engine.

- **Monitor the engine s behavior** after installation. If you notice persistent vibrations or unusual noises, revisit the installation or consult a mechanic.

For a classic vehicle like your Suburban, investing in quality parts like the SX-3487 is a **proactive step** to preserve its performance and reliability for years to come. The **benefits outweigh the risks**, provided you source the part correctly and perform the installation with care.

Details:

Dayco Engine Harmonic Balancer for 1969-1974 GMC C15 C1500 Suburban 5.7L V8 iu: Status: In Stock.

specifications cranshafengin:

  • for models: C1500, Suburban
  • for makes: Gmc
  • for years: 1969-1974
  • brand: Powerbond By Dayco
  • mpn: Sx-3487
  • item weight: 11.1100
  • ipn: C254 17-42
  • placement on vehicle: Engine Cylinder Block
  • compatible model: C15/c1500 Suburban
  • compatible year: 1974 1973 1972 1971 1970 1969
  • core charge: Free No Core Charge
  • type: Engine Harmonic Balancer
  • fitment type: Direct Replacement
  • bundle description: 1 Pc Genuine Dayco Engine Harmonic Balancer
  • timing marks: Yes
  • overall width: 2.343 In / 59.50 Mm
  • hardware included: No
  • ring width: 1.319 In / 33.48 Mm
  • counterweight balance: Neutral, No Counterweight
  • outer ring material: Grey Iron
  • overall outside diameter: 7.993 In / 203.00 Mm
  • nose outside diameter: 1.763 In / 44.78 Mm
  • crank bore: 1.245 In / 31.60 Mm

shipping cranshafengin:

  • class: Standard, Expedited
  • type: Fixed
  • transit: 2-6 Days
  • service: Standard, Expedited
  • cost: $0.00

returns cranshafengin:

  • policy: Returns Accepted
  • paid by: Seller
  • time: 30 Days

payments cranshafengin:

  • other
  • wallet: Apple-pay
  • credit card: Visa

general cranshafengin:

  • Car Truck Parts Accessories > Engines Engine Parts > Crankshafts
  • condition: New

offer cranshafengin:

  • quantity: 1
  • options: Ship-to-home
  • sold: 0
  • availability: In Stock
  • started: May 13, 2026

seller cranshafengin:

  • rating: 99.6%
  • # reviews: 656452
  • city: Indianapolis, Indiana
for models: c1500, suburban, for makes: gmc, for years: 1969-1974, item weight: 11.1100, placement on vehicle: engine cylinder block, compatible model: c15/c1500 suburban, compatible year: 1974 1973 1972 1971 1970 1969, core charge: free no core charge, type: engine harmonic balancer, fitment type: direct replacement, bundle description: 1 pc genuine dayco engine harmonic balancer, timing marks: yes, overall width: 2.343 in / 59.50 mm, hardware included: no, ring width: 1.319 in / 33.48 mm, counterweight balance: neutral, no counterweight, outer ring material: grey iron, overall outside diameter: 7.993 in / 203.00 mm, nose outside diameter: 1.763 in / 44.78 mm, crank bore: 1.245 in / 31.60 mm,
category: auto parts > car truck parts accessories > engines engine parts > crankshafts, sku: 20335969133739603,
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