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Tri-Five Chevys, produced between 1955 and 1957, are iconic vehicles known for their classic styling and performance potential. As enthusiasts seek to enhance power handling and overall performance, upgrading the transmission becomes a critical consideration. This article explores the best transmission upgrades for Tri-Five Chevys, focusing on the transition from the TH350 to the 700R4.
Understanding the TH350 Transmission
The TH350 transmission is a three-speed automatic that has been a popular choice for many classic car enthusiasts. Its simplicity and reliability make it a go-to option for those looking to replace or upgrade their original transmission. However, while it can handle moderate power levels, it may struggle under more demanding conditions.
Features of the TH350
- Three-speed automatic operation.
- Lightweight design for improved performance.
- Widely available replacement parts.
- Good for stock to moderate horsepower applications.
Limitations of the TH350
While the TH350 is a solid transmission, it does have limitations, especially for those looking to push the performance envelope. Its design may not hold up well under high torque conditions, leading to potential failure. Additionally, the lack of overdrive can result in higher RPMs at highway speeds, reducing fuel efficiency.
Introducing the 700R4 Transmission
The 700R4 is a four-speed automatic transmission that offers several advantages over the TH350. Its overdrive gear provides better fuel economy and lower engine RPMs at cruising speeds, making it a popular choice for those who drive their Tri-Five Chevys regularly.
Benefits of the 700R4
- Four-speed operation with overdrive.
- Improved fuel efficiency on the highway.
- Handles higher horsepower and torque levels.
- More versatile for various driving conditions.
Comparing TH350 and 700R4
When considering an upgrade from the TH350 to the 700R4, it is essential to compare their features and performance capabilities. The following table summarizes key differences:
- Gear Ratios: TH350 has a 2.52:1 first gear, while the 700R4 features a 3.06:1 first gear for better acceleration.
- Overdrive: The 700R4 includes an overdrive gear, reducing engine RPMs during highway cruising.
- Power Handling: The 700R4 is designed to handle more power, making it suitable for high-performance applications.
- Weight: The TH350 is lighter, but the 700R4 offers better overall performance.
Installation Considerations
Upgrading to a 700R4 transmission requires careful consideration of installation factors. Here are some key points to keep in mind:
- Crossmember Modification: The 700R4 may require adjustments to the crossmember for proper fitment.
- Driveshaft Length: A new driveshaft may be necessary due to the different output shaft length.
- Transmission Cooler: An upgraded transmission cooler is recommended to manage heat effectively.
- Shifter Compatibility: Ensure that the shifter is compatible with the 700R4 or consider an aftermarket solution.
Performance Modifications for the 700R4
To maximize the performance of the 700R4 transmission, several modifications can be made. These enhancements can improve shift quality and increase durability:
- Shift Kit: Installing a shift kit can provide firmer shifts and reduce slippage.
- Upgraded Torque Converter: A higher stall torque converter can improve acceleration and responsiveness.
- Transmission Control Module: For electronic versions, tuning the control module can optimize shifting patterns.
- Stronger Clutch Packs: Upgrading to stronger clutch packs can enhance power handling capabilities.
Conclusion
Upgrading from the TH350 to the 700R4 transmission in a Tri-Five Chevy can significantly enhance the vehicle’s performance and power handling capabilities. While the TH350 serves well for moderate applications, the 700R4 offers the benefits of overdrive and improved durability, making it an ideal choice for enthusiasts looking to maximize their classic car’s potential.