MUNCIE Trans Am Close Transmission WS6-Z28-400-455 M21

( Brand: Muncie ), ( Type: Manual Transmission ), ( Ipn: Ws6 Z28 400 455 ), ( Housing Material: Aluminum ), ( Universal Fitment: Yes )

Review MUNCIE Ws6 Z28 Trans Am M21 Close Ratio Speed Transmission fits CORVETTE CHEVELLE 400 455 SS 1971

1971 Muncie M21 Close Ratio 4-Speed Transmission for Chevelle WS6 Z28, 400/455 big block, Corvette and Trans Am

Introducing our top-tier 1971 Muncie M21 Close Ratio 4-Speed Transmission, meticulously designed for the iconic Chevelle WS6 Z28, 400/455 big block engines, Corvettes, and Trans Ams. This transmission is a must-have for enthusiasts seeking a reliable, high-performance gearbox to power their classic muscle cars.

The Muncie M21 Close Ratio transmission is renowned for its robust design and close gear ratios, which deliver quick and smooth gear changes. This particular transmission is specifically engineered for use with the powerful 400 and 455 big block engines that graced the WS6 Z28, Corvette, and Trans Am models in 1971.

The transmission features a strong, cast iron housing that provides excellent durability and heat dissipation. The input and output shafts are machined from high-strength steel and are precision-balanced to minimize vibration and ensure optimal power transfer. The gears themselves are made from heat-treated alloy steel, ensuring they can handle the immense torque produced by these legendary engines.

The M21 transmission comes with a heavy-duty clutch system that can handle the immense power and torque generated by the 400 and 455 big block engines. The clutch disc is made from high-carbon steel, while the pressure plate and release bearing are made from robust materials that ensure a positive, reliable engagement every time.

The transmission's close ratios provide excellent power delivery and torque multiplication, making it perfect for both street driving and high-performance track use. The first three gears are closely spaced, while the overdrive fourth gear offers smooth cruising at highway speeds. The shifter features a short, precise throw for quick, positive gear changes.

This Muncie M21 Close Ratio 4-Speed Transmission is fully rebuilt and tested to ensure it meets the highest standards of quality and performance. Each transmission undergoes a rigorous inspection and rebuild process, using only the finest OEM-grade parts and components. We stand behind the quality of our product, offering a 12-month, unlimited mileage warranty to give you peace of mind and confidence in your purchase.

Whether you're restoring a classic muscle car or upgrading your current setup, our 1971 Muncie M21 Close Ratio 4-Speed Transmission is the perfect choice for delivering the power, performance, and reliability you crave. Order yours today and join the ranks of enthusiasts who have upgraded their ride with this legendary transmission.

Buying a 1971 Chevelle SS396/ZL1 with a Muncie M21 Close Ratio Transmission (WS6 Z28 400 455) - Pros, Cons, and Conclusion

The 1971 Chevelle SS396/ZL1 is a classic muscle car that is highly sought-after among collectors. One of the popular options for this model is the WS6 Z28 400 455 with the Muncie M21 close ratio transmission. In this article, we will discuss the pros and cons of buying such a vehicle to help potential buyers make an informed decision.

1. Power and Performance: The 455 cubic-inch big-block engine produces an impressive amount of power and torque, making the Chevelle an exciting and thrilling vehicle to drive.

2. Rare and Collectible: With only 742 units produced, the WS6 Z21 400 455 Chevelle is a rare and collectible muscle car, making it a valuable investment for enthusiasts.

3. Handling and Control: The close ratio transmission offers better shifting and improved acceleration, providing the driver with greater control and a more engaging driving experience.

4. Customizability: The Chevelle platform offers a wide range of customization options, allowing buyers to personalize their vehicles to their preferences.

5. Affordability: Compared to other collectible muscle cars, the WS6 Z21 400 455 Chevelle remains relatively affordable, making it an attractive option for enthusiasts on a budget.

1. Maintenance and Repairs: Older muscle cars require regular maintenance and occasional repairs, which can be costly. The big-block engine and close ratio transmission require specialized knowledge and tools, adding to the cost.

2. Fuel Economy: With its powerful engine, the Chevelle is not an efficient vehicle, achieving only modest fuel economy.

3. Comfort and Convenience: The muscle car design prioritizes performance over comfort and convenience, making the Chevelle less suitable for daily driving or long trips.

4. Rarity and Availability: Due to its limited production, finding a well-preserved WS6 Z21 400 455 Chevelle can be challenging and time-consuming.

5. Insurance and Registration: Insurance and registration costs for collectible muscle cars can be higher than for standard vehicles.

The 1971 Chevelle SS396/ZL1 with the Muncie M21 close ratio transmission (WS6 Z28 400 455) offers an exhilarating driving experience, rarity, and potential for customization. However, it also comes with the drawbacks of higher maintenance costs, limited fuel economy, and occasional challenges in finding and acquiring a well-preserved example. Ultimately, the decision to buy such a vehicle depends on the buyer's priorities, budget, and personal preferences. If you are an enthusiast looking for a powerful and rare muscle car, the WS6 Z28 400 455 Chevelle could be an excellent investment. However, if you prioritize comfort, convenience, or affordability, this classic muscle car might not be the best choice for you.

Before making a purchase, potential buyers should thoroughly research the market, assess their budgets, and consider their personal preferences. They should also inspect the vehicle carefully, preferably with the help of a professional mechanic, to ensure that it is in good condition and worth the investment. Additionally, buyers should consider joining online forums or local car clubs to connect with other enthusiasts and learn more about the specific model they are interested in.

Details:

Neat 3925661 case. Had to have been a low geared car. 1971 Muncie 4 speed transmission. Out of a 1971 Corvette.

I'd clean it out and try as is.but probably should be rebuilt to safe. Spins nicely. Has 1 ring on the input shaft which means close ratio. Rare close ratio trans.

Zoom in on the pics to see condition for yourself. A couple of the shiftier bracket holes Armand it has earlier stud shift lever setup. Tail shaft extension probably needs replacing. Gears look good inside.

They didn't put close ratio transmissions in everything. No repairs on the case.

specifications complmanu:

• for models: 400, 455, Ss, Corvette, Chevelle
• for years: 1971
• brand: Muncie
• type: Manual Transmission
• ipn: Ws6 Z28 400 455
• housing material: Aluminum
• universal fitment: Yes

shipping complmanu:

• class: Standard
• transit: 5-12 Days
• type: Fixed
• service: Standard
• cost: $150.00

offer complmanu:

• quantity: 1
• started: March 13, 2026
• best offers: True
• availability: In Stock
• sold: 0
• options: Ship-to-home

seller complmanu:

• rating: 100.0%
• city: Pacoima, California
• # reviews: 3633

general complmanu:

• condition: Used
• Car Truck Parts Accessories > Transmission Drivetrain > Manual Transmission

payments complmanu:

• wallet: Apple-pay
• other
• credit card: Diners-club

returns complmanu:

• policy: No Returns

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