1. Engine Crankshafts Products
  2. sku: 19131840137932722
  3. MOLNAR 340-3580EF6F

MOLNAR TECHNOLOGIES 340-3580EF6F Forged Crank Pin 3.580 2.125

fits model: 580, 125, Sbm.

340-3580ef6f Molnar Technologies Sbm Forged Crank 3.580 Stroke With 2.125 Pin

( Brand: Molnar Technologies ), ( Manufacturer Part Number: 340-3580EF6F ), ( Part Type: Crank Pin ), ( Performance Part: Yes )

Review MOLNAR TECHNOLOGIES Forged Crank 3.580 Stroke 2.125 Pin fits SBM 580 125

The **Molnar 340-3580EF6F SBM Forged Crankshaft** represents the pinnacle of precision engineering and performance optimization for high-output, street and strip applications, particularly tailored for engines with a 3.580-inch stroke and 2.125-inch rod journals. Crafted from **SBM (Super Ballistic Molded) forged steel**, this crankshaft is designed to deliver uncompromising strength, durability, and reliability under extreme stress, making it an ideal choice for forced-induction builds, nitrous applications, or high-revving engines pushing beyond 10,000 RPM. The **340-degree rod journal offset** is a signature feature of Molnar s design philosophy, allowing for a more compact crankshaft package while maintaining optimal balance and power delivery. This offset reduces the overall length of the crank, which can improve piston-to-valve clearance and reduce reciprocating mass, contributing to smoother operation and enhanced high-RPM performance.

The **3.580-inch stroke** is achieved through meticulous forging and machining processes, ensuring consistent wall thickness and uniform material properties throughout the crank s critical sections. The **2.125-inch rod journals** are precision-ground to exacting tolerances, with **hardened and ground main and rod journals** to withstand the rigors of high torque and lateral forces generated by aggressive camshaft profiles, turbocharging, or supercharging. Molnar s **SBM forging process** involves a proprietary method of molding the steel under extreme pressure, eliminating internal voids and creating a denser, more homogeneous structure than traditional castings or conventional forgings. This results in a crankshaft with superior fatigue resistance, making it capable of enduring the relentless demands of high-performance applications without the risk of catastrophic failure.

The **counterweight design** is another standout feature, meticulously balanced to minimize vibration and maintain smooth operation even under extreme loads. Molnar s engineers have optimized the counterweights to reduce harmonic distortion, which is particularly beneficial for engines running with aggressive camshafts or high compression ratios. The **main journal spacing** is carefully calculated to ensure proper crankshaft alignment within the engine block, reducing stress on the bearings and extending their lifespan. Additionally, the **fillets and transitions** between the journals and the crank arms are smoothly blended, further enhancing durability by preventing stress concentrations that could lead to premature wear or failure.

For applications requiring maximum reliability, the **Molnar 340-3580EF6F** is often paired with Molnar s **SBM forged connecting rods**, creating a fully matched set that works in perfect harmony to deliver peak performance. Whether installed in a **LS-based engine, a small-block Chevy, or a high-revving V8**, this crankshaft is engineered to handle the most demanding scenarios, from street-driven muscle cars to full-race applications. Its **forged construction** ensures it can handle the thermal and mechanical stresses of forced induction without warping or losing dimensional stability, while the **precision machining** guarantees a perfect fit with aftermarket components, including custom pistons, rods, and bearings. In summary, the Molnar 340-3580EF6F SBM Forged Crankshaft is not just an upgrade it s a performance-enhancing masterpiece designed to push engines to their absolute limits while maintaining the integrity and longevity expected from Molnar s legendary reputation for excellence.

### Pros and Cons of buying a Molnar 340-3580EF6F SBM Forged Crank (3.580" Stroke, 2.125" Pin)

#### **Pros:**

1. **High-Quality Forging Process** Molnar cranks are forged from premium steel, ensuring superior strength, durability, and resistance to fatigue. This makes them ideal for high-performance applications, including forced induction and heavy-duty use.

2. **Balanced Weight Distribution** The forged construction allows for precise machining, resulting in a well-balanced crankshaft that reduces vibration and improves engine smoothness. This is particularly beneficial for high-RPM applications.

3. **Strength and Reliability** The SBM (Single Bolt Main) design, combined with forged construction, provides exceptional strength, making it suitable for aggressive builds, including turbocharged or supercharged engines. It can handle higher torque loads without compromising integrity.

4. **Precision Machining** Molnar cranks undergo rigorous machining processes, ensuring tight tolerances and optimal performance. This attention to detail helps maintain efficiency and longevity in demanding applications.

5. **Compatibility with High-Performance Engines** The 3.580" stroke is well-suited for engines requiring increased displacement without excessive weight or complexity. The 2.125" pin diameter also contributes to better piston-to-wall clearance and reduced stress on connecting rods.

6. **Warranty and Support** Molnar is a reputable manufacturer with strong customer support and warranties, which can provide peace of mind for serious builders.

7. **Customization Options** Molnar offers various crankshaft configurations, including different stroke lengths and rod journal sizes, allowing for tailored builds to match specific engine requirements.

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#### **Cons:**

1. **Cost** Forged cranks, especially from high-end manufacturers like Molnar, are significantly more expensive than cast or stock cranks. This can be a substantial investment, particularly for enthusiasts on a budget.

2. **Installation Complexity** Replacing a crankshaft requires significant disassembly of the engine, including removing the block, pistons, and rods. This process is labor-intensive and may require professional assistance, adding to the overall cost.

3. **Compatibility Issues** While Molnar cranks are versatile, ensuring compatibility with your existing engine components (e.g., rods, bearings, and block) is critical. Improper fitment can lead to performance issues or damage. Consultation with an engine builder is advisable.

4. **Weight** Forged cranks are heavier than cast counterparts, which can slightly reduce high-RPM performance due to increased rotating mass. However, this is typically negligible in most applications and outweighed by the strength benefits.

5. **Limited Aftermarket Support** While Molnar is well-regarded, some aftermarket parts (e.g., rods, bearings) may not be as widely available or optimized for Molnar cranks compared to more common OEM or aftermarket options.

6. **Potential Overkill for Mild Builds** If you re running a naturally aspirated engine with modest power goals, a forged Molnar crank may offer more strength than necessary, making it a less cost-effective choice.

7. **Learning Curve** Building an engine with a forged crank requires a good understanding of engine mechanics. Novice builders may benefit from consulting experienced mechanics or engine builders to avoid mistakes.

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### **Conclusion:**

The Molnar 340-3580EF6F forged crank is an excellent choice for high-performance applications, particularly for engines requiring increased displacement, forced induction, or aggressive power goals. Its forged construction, balanced design, and strength make it a reliable and durable option for serious builders. However, the high cost, installation complexity, and potential overkill for mild builds must be carefully considered.

If you re planning a high-RPM, high-torque build such as a turbocharged or supercharged engine this crank is a strong recommendation. For more modest projects, a cast or stock crank may suffice and save costs without sacrificing performance.

### **Recommendation:**

- **Buy it if:** You re building a high-performance engine (e.g., turbocharged, supercharged, or high-RPM NA) and prioritize strength, durability, and reliability. Ensure your engine components (rods, bearings, block) are compatible.

- **Avoid it if:** You re on a tight budget, building a mild NA engine, or lack experience with engine assembly. In such cases, a high-quality cast crank or OEM replacement may be more practical.

- **Consider alternatives:** If cost is a concern, explore other forged crank manufacturers (e.g., JE, Scat, or ARP) or high-quality cast cranks (e.g., Scat, JE) that offer a balance of performance and affordability. Always consult an engine builder to confirm fitment and compatibility.

Details:

Crankshaft - 3.580 in Stroke Internal Balance Forged Steel 2-Piece Seal 340 Mains Small Block Mopar Each. Manufacturer: Molnar Technologies.

part #: 3403580ef6f prices

  • $1307.99-$1442.60

specifications cranshafengin:

  • for models: 580, 125, Sbm
  • brand: Molnar Technologies
  • mpn: 340-3580ef6f
  • part type: Crank Pin
  • performance part: Yes

seller cranshafengin:

  • # reviews: 122736
  • rating: 99.8%
  • city: San Leandro, California

offer cranshafengin:

  • quantity: 1
  • availability: In Stock
  • sold: 0
  • started: March 2, 2026
  • options: Ship-to-home

general cranshafengin:

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

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  • wallet: Apple-pay
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  • credit card: Visa

shipping cranshafengin:

  • class: Standard
  • type: Fixed
  • cost: $0.00
  • service: Standard
  • transit: 3-7 Days

returns cranshafengin:

  • time: 30 Days
  • paid by: Seller
  • policy: Returns Accepted
for models: 580, 125, sbm, part type: crank pin, performance part: yes,
category: auto parts > car truck parts accessories > engines engine parts > crankshafts, sku: 19131840137932722,
Molnar Technologies 340-3580EF6F Is Similar To:
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5 offers $1307.99–$1442.60 USD
  • New. Offer #1 priced at $1307.99 + $0.00 shipping estimate = $1307.99* total. Crankshaft - 3.580 in Stroke - Internal Balance - Forged Steel - 2-Piece Seal - Small Block Mopar - Each.FREE SHIPPING
  • New. Offer #2 priced at $1377.19 + $0.00 shipping estimate = $1377.19* total. Crankshaft - 3.580 in Stroke - Internal Balance - Forged Steel - 2-Piece Seal - 340 Mains - Small Block Mopar - Each. Manufacturer: Molnar Technologies.FREE SHIPPING
  • New. Offer #3 priced at $1442.60 + $0.00 shipping estimate = $1442.60* total. If a defect is identified after this period, it will fall under the manufacturer's warranty and should be handled directly with them.FREE SHIPPING
  • New. Offer #4 priced at $1411.67 + $79.00 shipping estimate = $1490.67* total. 340-3790EB6F Small Block Chrysler -2.100" Rod Pins 3.790 340 2.100 6.123 1850. CHRYSLER SMALL BLOCK FORGED CRANKS.+$79.00 shipping
  • New. Offer #5 priced at $1411.67 + $79.00 shipping estimate = $1490.67* total. +$79.00 shipping

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