GENUINE GM PARTS 12621773 Engine Cylinder Head 195491257955

( Brand: Genuine Gm Parts ), ( Manufacturer Part Number: 12621773 ), ( Manufacturer Warranty: 1 Year ), ( Core Charge: 75.00 Which Is Included In The Total Price ), ( Type: Engine Cylinder Head ), ( UPC: 195491257955 )

Review GENUINE GM PARTS Engine Cylinder Head

The **GM 12621773 Engine Cylinder Head** is a precision-engineered component designed specifically for select General Motors (GM) small-block V8 and high-performance applications, offering a blend of durability, performance, and reliability. Crafted from high-quality cast iron, this cylinder head is meticulously machined to exacting tolerances to ensure optimal combustion efficiency, thermal management, and structural integrity under high-stress conditions. The head features a robust valve train system, including hardened valve seats and precision-ground valve guides, which work in tandem with the pushrods and rocker arms to deliver smooth, responsive operation while minimizing wear and tear. Its integrated combustion chamber design promotes efficient fuel-air mixture combustion, enhancing both power output and fuel economy, making it an ideal choice for both street and track applications.

The GM 12621773 cylinder head is equipped with a robust valve cover, often featuring integrated oil filler and breather ports, ensuring proper ventilation and preventing oil aeration. The head also incorporates a cast-in exhaust port design optimized for airflow, reducing backpressure and improving exhaust scavenging, which is critical for maximizing horsepower and torque in high-performance engines. For applications requiring additional strength, this head may include reinforced valve springs and retainers, as well as hardened valve stems to withstand the stresses of forced induction or high-revving engines. The head s bolt pattern and mounting surfaces are engineered to align seamlessly with the engine block, ensuring a secure and leak-free seal when paired with the appropriate gaskets and head studs.

Whether installed in a stock GM small-block V8 or a heavily modified high-performance engine, the GM 12621773 cylinder head is built to meet the demands of modern automotive engineering. Its compatibility with aftermarket upgrades, such as performance camshafts, high-flow intake and exhaust manifolds, and turbocharging systems, makes it a versatile component for enthusiasts seeking to enhance their vehicle s performance. With its robust construction and precision engineering, this cylinder head is a reliable choice for those looking to balance strength, efficiency, and performance in their GM-powered engines.

**Pros and Cons of Buying a GM 12621773 Engine Cylinder Head**

The GM 12621773 cylinder head is commonly associated with the 3.4L V6 engine found in vehicles like the Chevrolet Malibu, Impala, and some GMC models. Below is a detailed breakdown of its advantages and disadvantages.

### **Pros**

1. **Widely Available Parts and Support**

The GM 3.4L V6 is a well-documented engine, meaning cylinder heads, gaskets, bolts, and other components are readily available from aftermarket suppliers, GM dealers, and online retailers. This makes repairs and modifications easier compared to less common engines.

2. **Proven Reliability with Proper Maintenance**

When maintained correctly including regular valve adjustments, proper oil changes, and cooling system checks the 3.4L V6 is known for lasting well over 200,000 miles. Many owners report few major issues if they address minor problems early.

3. **Modification and Performance Potential**

The 3.4L V6 is a popular choice for engine swaps and performance builds due to its compact size, strong stock power (around 170 200 hp in stock form), and compatibility with aftermarket upgrades. Head swaps, porting, and camshaft installations are common, allowing for significant power gains.

4. **Lower Cost Compared to New Engines**

Replacing a cylinder head (or heads) is often cheaper than buying a complete engine rebuild or replacement. A used or remanufactured head can cost significantly less than a brand-new OEM part, though quality varies.

5. **Compatibility with Common Upgrades**

The 3.4L V6 benefits from aftermarket parts like high-flow intake manifolds, performance exhaust headers, and upgraded cooling systems. This makes it a flexible platform for both daily drivers and enthusiasts.

6. **Good Aftermarket Support for Common Issues**

Problems like leaking valve cover gaskets, head gasket failures (though less common than in older GM V8s), and worn rocker arms have well-documented fixes. Online forums (such as those on GM forums or engine-specific sites) provide troubleshooting advice.

7. **Remanufactured Options Available**

Companies like **Eagle, JE, and Summit Racing** offer remanufactured cylinder heads that come with warranties, reducing the risk of buying a used part with hidden damage.

---

### **Cons**

1. **Head Gasket Failures Can Be Costly**

While less frequent than in older GM engines, head gasket leaks or blowouts can occur, especially if the engine overheats or lacks proper maintenance. A head gasket replacement requires removing both cylinder heads, which adds labor cost.

2. **Valvetrain Wear Over Time**

The pushrods, rocker arms, and lifters in the 3.4L V6 can wear out, leading to excessive valve lash or even valve float at high RPMs. Regular valve adjustments (every 60,000 100,000 miles) are necessary to prevent damage.

3. **Oil Leaks from Valve Cover and Oil Filter Housing**

The valve cover gasket and oil filter housing gasket are common leak points. These are relatively easy to fix but require periodic inspection, especially if the engine is modified or driven hard.

4. **Limited Stock Power for Modern Standards**

The stock 3.4L V6 produces around **170 200 hp**, which is adequate for a daily driver but lacks the power of modern turbocharged or high-performance engines. For serious performance builds, significant modifications (turbocharging, forced induction) are needed.

5. **Remanufactured Parts May Not Be Perfect**

While remanufactured cylinder heads are a cost-effective option, some may have inconsistencies in machining or sealing surfaces. Buying from reputable suppliers with warranties helps mitigate this risk.

6. **Compatibility Issues with Some Modifications**

Not all aftermarket parts (especially high-flow headers or turbochargers) are designed specifically for the 3.4L V6. Improperly matched components can cause issues like backpressure or cooling problems.

7. **Potential for Cooling System Failures**

The 3.4L V6 is prone to overheating if the cooling system (radiator, thermostat, water pump) is neglected. A failed water pump or clogged radiator can lead to catastrophic engine damage if not addressed promptly.

8. **Limited Longevity with Heavy Modifications**

While the 3.4L V6 can handle forced induction, aggressive camshafts, or high RPMs, pushing it too hard without proper supporting modifications (strengthened rods, upgraded oil pump, etc.) can lead to premature failure.

---

### **Conclusion**

The **GM 12621773 cylinder head** is a solid choice for those maintaining or modifying a 3.4L V6 engine, provided proper care is taken. Its **wide availability of parts, reliability with maintenance, and strong aftermarket support** make it a practical option for both daily drivers and enthusiasts. However, **potential issues like head gasket failures, valvetrain wear, and oil leaks** require vigilance, especially in high-mileage or modified engines.

For **stock or lightly modified applications**, the 3.4L V6 remains a dependable powerplant. For **serious performance builds**, additional investments in supporting components (cooling, fueling, valvetrain) are necessary to avoid premature failure.

---

### **Recommendation**

- **Buy a remanufactured head from a reputable supplier** (e.g., Eagle, JE, Summit Racing) with a warranty.

- **Inspect the block and other components** for signs of wear (warped surfaces, cracks) before installation.

- **Follow proper torque specifications** for bolts and gaskets to prevent leaks.

- **Upgrade the cooling system** (radiator, water pump, thermostat) to handle increased heat.

- **Replace the valvetrain** (pushrods, rocker arms, lifters) if the engine is high-mileage.

- **Consider a head swap or porting** if stock power is insufficient, but ensure compatibility with intake and exhaust upgrades.

- **Monitor oil pressure and temperature** closely, as forced induction or high RPMs increase stress on the engine.

- **Avoid heads with visible cracks, warping, or excessive pitting.**

- **Check for proper machining** (valve seats, combustion chamber surfaces).

- **Test-fit the head on the block** to ensure a proper seal before purchasing.

Overall, the **GM 12621773 cylinder head is a sound investment** for those willing to maintain it properly, but it requires attention to detail to avoid common failure points. For maximum longevity, **regular maintenance and timely repairs** are essential.

Details:

See below for instructions. Return Core as: Money Back. High-value items are usually sent with signature-delivery requirements. This part fits vehicles made in the following years 2009 ,2010, 2011 ,2012,2013.

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part #: 12621773 prices

• $843.28-$925.25

specifications cylinderheapar:

• brand: Genuine Gm Parts
• mpn: 12621773
• manufacturer warranty: 1 Year
• core charge: 75.00 Which Is Included In The Total Price
• type: Engine Cylinder Head
• upc: 195491257955

shipping cylinderheapar:

• service: Standard
• type: Fixed
• class: Standard
• cost: $0.00
• transit: 18-28 Days

offer cylinderheapar:

• options: Ship-to-home
• sold: 0
• quantity: 5
• started: May 16, 2026
• availability: In Stock

general cylinderheapar:

• Car Truck Parts Accessories > Engines Engine Parts > Cylinder Heads
• condition: Remanufactured

payments cylinderheapar:

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

returns cylinderheapar:

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

seller cylinderheapar:

• # reviews: 19119
• rating: 99.2%
• city: Garland, Texas

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