Tremec TKX 5-Speed Mustang Swap Guide | California Pony Cars
The Complete Guide to the Tremec TKX 5-Speed Swap for Classic Mustangs
Featuring California Pony Cars Conversion Components
For more than 35 years, California Pony Cars has engineered bolt-in 5-speed conversion systems designed to improve drivability, reliability, and highway comfort in 1964–1973 Mustangs. Early in the classic Mustang restoration era, California Pony Cars recognized the need for a dependable overdrive solution that lowered cruising RPM, improved fuel economy, and delivered modern drivability without cutting the tunnel or altering the original structure of the vehicle.
Those principles remain at the core of today's Tremec TKX 5-speed conversion. The TKX represents the next evolution of the classic overdrive upgrade, and California Pony Cars continues to support Mustang owners with a fully engineered, USA-made bolt-in system that preserves authenticity while offering modern performance.
This guide explains why the Tremec TKX has become the preferred transmission for classic Ford restorations, how it compares to earlier T5 and TKO models, and how California Pony Cars provides the components required to complete a true no-modification conversion.
The Evolution of Mustang 5-Speed Swaps
More than three decades ago, the T5 World Class transmission was widely available in salvage yards and became the go-to transmission for owners seeking an economical 5-speed upgrade. California Pony Cars developed the first true bolt-in T5 conversion system for classic Mustangs, allowing owners to gain overdrive without modifying the tunnel, drilling holes, or reducing the car's collector value.
As power levels increased and the supply of T5 units declined, builders searched for stronger options. This led to the Tremec TKO, which later evolved into the Tremec TKX. The TKX improves on the TKO with a more compact case, better shift feel, more efficient gearing, higher RPM capability, and smoother synchronization. It fits more easily into classic Mustangs, and when paired with California Pony Cars conversion components, it installs with no cutting.
California Pony Cars has continued to refine Mustang-specific transmission components since the introduction of the T5. The TKX conversion represents the next step in that evolution, providing modern performance while maintaining a classic driving experience.
Why the Tremec TKX Is the Premier Upgrade
The Tremec TKX transmission, available from California Pony Cars as Part Number TRA-000-361, delivers significant improvements over the older T5 and TKO units.
Key features include:
600 lb-ft torque capacity
Capable of operating at 8000 RPM with shift capability up to 7500 RPM
Compact 3-piece aluminum case designed to clear classic Mustang tunnels
Lightweight 99-pound dry weight
Modern synchronizers for smoother shifts
Multiple shifter locations for precise placement
26-spline Ford input
Strong 3-rail internal shift mechanism
0.68 overdrive for lower highway RPM
Gear ratios:
1st: 2.87
2nd: 1.89
3rd: 1.28
4th: 1.00
5th: 0.68
Reverse: 2.56
Real-world benefits include lower cruising RPM, reduced engine wear, improved fuel efficiency, smoother shifting, better drivability on long trips, and dependable shifting for high-performance engines.
California Pony Cars: Pioneers of Mustang 5-Speed Conversions
For more than 35 years, California Pony Cars has been a leading innovator of bolt-in Mustang 5-speed conversions. When the company first introduced its T5 conversion system, Mustang owners had limited options for improving drivability without altering the vehicle's originality. CPC engineers developed a complete system that used as many stock components as possible and allowed installation with no structural modifications.
This philosophy continues with TKX conversions. Each CPC component is engineered to match factory geometry, restore proper driveline angles, and ensure long-term reliability. Components are manufactured in the United States using high-quality materials and backed by a lifetime warranty.
CPC conversion parts are used by high-end restoration shops worldwide, including Eleanor-style builders and international performance restoration facilities. These components have been proven on the street, at shows, and in long-distance touring applications.
What Sets CPC Conversion Components Apart
USA-made engineering
Lifetime warranty
True bolt-in fitment
Compatibility with many original Mustang components
Decades of proven durability
No cutting or welding required
Key CPC Parts for a Complete TKX Conversion
TRA-000-361 – Tremec TKX Transmission
TRA-000-397 – Aluminum Bellhousing
TRA-650-702 – Adapter Plate Kit (Toploader Bellhousing to TKX)
TRA-656-639 / TRA-650-702 – Crossmember Bar
TRA-000-415 – Billet Shifter Lever and Knob
TRA-657-516 – T5 5-Speed Shift Lever
Other parts that may be required:
TRA-650-521 Transmission Mount Insulator
TRA-000-377 AOD Transmission Neutral Safety / Back- Up Light Switch Pigtail
TRA-000-372 Separator Block Plate
TRA-658-718 T5 Clutch Cable Linkage
TRA-678-745 Mustang/Cougar Clutch Cable Conversion Kit
TRA-000-151 Spline Slip Yoke
TRA-000-048 10.5 inch Diaphragm-Type Clutch Kit
Installation Tips and Best Practices
Use 2.75 quarts of Dexron III automatic transmission fluid
Choose a clutch kit based on engine horsepower
Ensure proper bellhousing alignment
Retain original clutch linkage when possible
Confirm speedometer cable compatibility
Common Myths and Misconceptions
A TKX installed with CPC components does not require cutting the transmission tunnel on 1964–1973 Mustangs. CPC conversions are engineered specifically to avoid structural modifications.
Proven Fitment Across Classic Ford Models
1964–1973 Mustang
1967–1973 Cougar
Ford Falcon
Ford Fairlane
Ford Ranchero
Classic F100 trucks
Early Bronco models
Why Southern California Relies on CPC
Local Tremec T5 and TKX inventory in the 91761 area
Same-day pickup options
Live technical support from an expert
Fast regional shipping
More than 35 years of Mustang conversion experience
Support available nationwide and worldwide
Build Your Complete Tremec TKX or T5 Conversion Package
California Pony Cars offers every major component required for a full TKX installation. Customers may purchase individual components or complete conversion packages.
Call to Action
For expert fitment assistance or to order a complete TKX conversion, contact California Pony Cars directly at 909-923-2357. When you call, you will always speak with a real person. We still answer the phones and provide live, knowledgeable support every time.
