CHEVROLET 386781 Big Block Cylinder Heads Cores

( Brand: Chevrolet ), ( Manufacturer Part Number: 386781 ), ( Part Type: Block Cylinder Head ), ( Material: Cast Iron ), ( Finish: Unfinished ), ( Country Of Origin: United States ), ( Performance Part: Yes )

Review CHEVROLET Big Block Chevy Cylinder Heads Cores Casting #386781 fits 1973–1976

The **Chevrolet 386781 1973 1976 Big Block Cylinder Heads Cores** represent a highly sought-after component for enthusiasts and restorers of classic American muscle, offering a blend of raw performance potential and historical authenticity. These cast iron cylinder heads, originally designed for the legendary **396 cubic inch and 454 cubic inch big block Chevy engines**, are the backbone of an era when power and torque were measured in horsepower and foot-pounds of torque rather than mere efficiency ratings. The **386781 designation** specifically refers to the **1973 1976 model year heads**, which feature a robust **4-valve-per-cylinder** design with **1.94-inch intake and 1.60-inch exhaust valves**, optimized for high-revving performance and aggressive camshaft profiles. The **cast iron construction** ensures durability under extreme conditions, while the **integrated valve springs and retainers** provide a classic, no-frills approach that appeals to purists. These heads are often paired with **mechanical lifters** and **solid or hydraulic flat-tappet cams**, delivering a throaty, growling exhaust note that is synonymous with the golden age of American muscle. Whether you're rebuilding a **ZL1 454**, a **SS 454**, or a **396-based high-performance engine**, these cores offer a solid foundation for restoring or upgrading your big block Chevy to its original glory or pushing it even further with modern modifications. The **1973 1976 iteration** also includes subtle refinements in port design and valve angle adjustments, making them a versatile choice for both street and strip applications. For those seeking a piece of automotive history with genuine performance pedigree, these cylinder heads are an essential component, bridging the gap between classic muscle and modern high-performance engineering.

Buying **Chevrolet 386781 1973 1976 Big Block Chevy cylinder heads cores** (used or aftermarket) can be a cost-effective solution for restoring or rebuilding a classic engine, but it comes with significant pros and cons. Below is a detailed breakdown, followed by a conclusion and recommendation.

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### **Pros of Buying Big Block Chevy Cylinder Heads (1973 1976, Part #386781)**

1. **Cost Savings Compared to New Heads**

- Used or aftermarket cores are far cheaper than brand-new factory or high-performance heads. Prices typically range from **$200 $600 per head**, depending on condition, brand, and modifications.

- Factory-new heads (e.g., from a dealer or specialty manufacturer like **Edelbrock, Holley, or JE**) can cost **$800 $1,500 per head**, making cores an attractive alternative.

2. **Availability of Modified or Performance Heads**

- Many aftermarket cores are **pre-drilled for hydraulic lifters, larger valves, or ported** for better airflow, which can improve horsepower without full machining.

- Some cores come from **high-performance builds**, offering a head start on tuning.

3. **Quick Turnaround for Restoration**

- If you re rebuilding an engine and need heads immediately, cores allow you to **skip the wait time** for new parts while still getting functional components.

- Some sellers offer **ported and polished cores**, saving you the labor cost of machining.

4. **Compatibility with Common Modifications**

- The **1973 1976 Big Block Chevy** (396/454/427) heads are widely supported by aftermarket parts, meaning you can easily upgrade valves, springs, and rocker arms.

- Many cores are **drop-in compatible** with stock or mild performance builds.

5. **Potential for Resale Value**

- If you plan to sell the engine later, **well-maintained cores** (especially from known brands or high-performance builds) can retain value.

- Some collectors and restorers prefer cores over fully rebuilt heads for authenticity.

6. **Easier to Find Than Full Heads**

- Cores are more commonly listed on **eBay, Facebook Marketplace, or specialty forums** than fully assembled heads, increasing your chances of finding a match quickly.

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### **Cons of Buying Big Block Chevy Cylinder Heads (1973 1976, Part #386781)**

1. **Variable Quality and Condition**

- Used cores may have **hidden damage** (cracks, warped decks, burnt valves, or worn valve seats) that isn t visible without inspection.

- Some sellers don t disclose **previous modifications** (e.g., aggressive porting that may not be ideal for your build).

- **Corrosion** is a common issue in older heads, especially if they ve been stored improperly.

2. **Machining and Rebuilding Required**

- Even if the cores are structurally sound, they **must be ported, polished, and valve-guided** to function properly, adding labor costs.

- **Deck mating** (flattening the top surface) is often necessary to ensure a proper seal with the cylinder block.

- **Valve seat replacement** is usually required, as seats wear out over time.

3. **Potential for Incompatibility**

- Some cores may have been **modified for a different application** (e.g., high-lift cam clearance, different valve sizes) that doesn t match your engine s specs.

- **Threaded holes** (for lifters, studs, or oil passages) may not align with your block, requiring additional machining.

4. **Risk of Scams or Misrepresented Parts**

- Sellers may **mislabel cores** as being from a specific year or engine variant (e.g., calling a 454 head a 396 head).

- Some "cores" are actually **scrap heads** with major issues, sold at a low price to unknowing buyers.

- **No return policy** once you buy, you re responsible for any issues.

5. **Limited Warranty or Guarantees**

- Unlike new heads from a dealer, used cores typically come with **no warranty**, meaning you bear all risks of failure.

- Aftermarket cores may have **limited warranties** (e.g., 30 90 days), but defects often go unnoticed until installation.

6. **Time-Consuming Inspection Process**

- Properly evaluating a core requires **visual inspection, pressure testing, and sometimes X-ray or ultrasonic testing** for cracks.

- If you re not experienced, you may **overlook critical issues**, leading to costly repairs later.

7. **Potential for Overpaying**

- Some sellers price cores **too high**, especially if they re from a "high-performance" build that doesn t match your needs.

- **Auction or eBay fees** can add to the cost, making the total expense closer to new heads.

8. **Environmental and Logistical Concerns**

- Shipping heavy cores (especially cast iron) can be **expensive and risky** (damage in transit).

- If buying locally, you may still need to **transport them carefully** to avoid warping or cracking.

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### **Key Considerations Before Purchase**

- **Where to Buy?**

- **eBay** (filter for "used cores" and check seller ratings).

- **Facebook Marketplace / Craigslist** (local pickups can save on shipping).

- **Specialty forums** (e.g., **Chevy101, Hemmings, or Big Block Chevy groups**) where sellers often provide more details.

- **Auctions** (e.g., Barrett-Jackson, Bring a Trailer) for high-end cores.

- **Aftermarket suppliers** (e.g., **Edelbrock, JE, or Summit Racing**) for modified cores.

- **Cracks** (use a **magnetic particle inspection** or dye penetrant test).

- **Deck flatness** (should be within **0.002 0.004" per side**).

- **Valve guides and seats** (should be intact, not burnt or cracked).

- **Port geometry** (check for **aggressive porting** if you want stock-like airflow).

- **Thread condition** (lifter bores, oil holes, and stud threads should be clean).

- **Warping** (use a **straightedge and feeler gauges** to check the deck).

- If you re **not comfortable with machining** and need heads that are **ready to install**.

- If you re building a **high-performance engine** and need **factory or high-end aftermarket heads** (e.g., **Edelbrock Torker, JE, or Holley**).

- If you re on a **tight budget** and can t afford the labor to prep them properly.

---

### **Conclusion**

Buying **1973 1976 Big Block Chevy cylinder heads cores (part #386781)** can be a **smart financial decision** if you re willing to put in the work to prepare them. They offer **significant cost savings** compared to new heads and can be a great way to **customize your build** with modified ports or valves. However, they come with **risks of hidden damage, compatibility issues, and additional labor costs** that must be carefully considered.

If you re **experienced with engine rebuilding** and can **inspect cores thoroughly**, they are a **viable option** especially for **restoration projects or mild performance builds**. If you re **new to engine work** or building a **high-performance engine**, investing in **new or high-quality aftermarket heads** may be more reliable in the long run.

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### **Final Recommendation**

- **Buy used cores** from a **trusted seller** (check reviews, ask for inspection photos, and consider local pickups).

- **Get them professionally inspected** (or learn to do it yourself) before purchasing.

- **Factor in machining costs** (porting, polishing, valve seat replacement) when calculating total expenses.

- **Purchase new or remanufactured heads** from a **dealer or reputable aftermarket supplier** (e.g., **Edelbrock, JE, or Summit Racing**).

- **Consider a used but fully rebuilt head** from a **trusted machine shop** if you want a balance between cost and reliability.

- **Invest in high-end aftermarket heads** (e.g., **Holley, Edelbrock Torker, or custom-built heads**) for optimal airflow and durability.

**Best Value Choice:** Used cores from a **verified seller** with **clear documentation** and a **detailed inspection** if you re prepared for the extra work.

**Easiest Choice:** New or remanufactured heads from a **dealer or specialty shop** if you want a turnkey solution.

Would you like recommendations on specific sellers, inspection methods,

Details:

1973-1976 Big Block Chevy Cylinder heads oval port, open chamber, Casting #386781. No machine work has been done. They are bare cores and sold as is. The cylinder heads for sale have been hot tanked and to insure they are not cracked suitable be rebuilt.

part #: 386781 price

• $500.00

specifications cylinderheapar:

• for makes: Chevy, Chevrolet
• for years: 1973-1976
• brand: Chevrolet
• mpn: 386781
• part type: Block Cylinder Head
• material: Cast Iron
• finish: Unfinished
• country of origin: United States
• performance part: Yes

offer cylinderheapar:

• quantity: 1
• sold: 0
• options: Ship-to-home
• availability: In Stock
• started: March 11, 2026

returns cylinderheapar:

• policy: No Returns

seller cylinderheapar:

• city: Euclid, Ohio
• # reviews: 66
• rating: 100.0%

shipping cylinderheapar:

• service: UPS Ground
• transit: 5-10 Days
• class: Standard
• cost: $75.22
• carrier: UPS
• type: Calculated

payments cylinderheapar:

• wallet: Paypal
• other
• credit card: Diners-club

general cylinderheapar:

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

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