MAKING GAS
March 19, 2024
THE AUTO BUILDER
Featured
SPRING TO ACTION
Dean Brown, a longtime rodder, was in the market for a new project car and stumbled across this ’52 Chevy panel truck, which turned out to be one of the original Helms trucks. The bakery cabinets had been removed but the body was in good condition, and it was still running with the original six-cylinder engine. Brown thought the truck was very cool, so he made a deal with its owner and drove it home. He formulated a plan of attack and started acquiring the parts he needed to turn it into a hot Chevy panel. The parts included a strong-running V-8 engine, a Turbo 350 transmission, a Fat Man Fabrications IFS front suspension and a new rear suspension that would provide a softer ride quality.
EARLY-IMPALA LS2 SWAP
Low in its architecture and functionally beautiful, the LS2 engine is an ideal replacement for a previous generation of Chevy powerplants. It offers good
performance, greatly improved economy and plenty of support from an industry leaders.
THE NATS EXPERIENCE
There are car shows, and then there’s the Nats. If you’ve been there, you know exactly what we mean. For four days, the Kentucky Exposition Center becomes its own hot rod city—more than 10,000 street rods, customs, classics, muscle cars, and trucks filling seemingly every available piece of pavement, with cars cruising the grounds and something new catching your eye everywhere you turn.
Spotlighter
PRODUCT SPOTLIGHT: Gearstar 4L65E Transmissions
Hand-Built for High-Performance
When building a high-performance vehicle or performing an LS engine swap, your transmission is just as critical as the engine. The 4L65E transmission from Gearstar offers the perfect balance of strength, reliability, and adaptability—custom-built to handle up to 650 horsepower and tailored to your exact specifications.
Author
The Auto Builder Staff
Photos Courtesy of Gearstar
Fits Like a Glove in Older Rides
Originally developed by GM as an upgrade to the 4L60E, the 4L65E was designed to meet the rising demands of performance vehicles. Though it looks nearly identical on the outside, it features internal enhancements—including a hardened input shaft, stronger sun shell, and a five-pinion rear planetary gear set. These enhancements make the 4L65E ideal for street performance, towing, or track use—easily handling more torque and heat than its predecessor.
Thanks to its two-piece case design and compact size, the 4L65E fits easily into most older vehicles without major modifications to the transmission tunnel. It’s a go-to option for hot rodders, classic car restorers, and custom builders alike.
Ideal for LS Engine Swaps
The 4L65E features a 7-bolt LS bellhousing pattern and a 13-pin main harness connector, making it highly compatible with modern GM engines and standalone transmission controllers. Whether your build is fuel injected or carbureted, Gearstar will configure your transmission to match your setup—including popular systems like Holley Sniper or Edelbrock Pro-Flo.
This level of adaptability has made the 4L65E one of the most popular transmissions for LS swap applications, especially for builds staying under the 650-horsepower mark.
Mopar-Compatible Transmission Option
For Mopar enthusiasts looking to modernize their drivetrain, Gearstar offers a version of the 4L60E/4L65E with a Mopar-specific bellhousing. Whether you’re running a Small Block, Big Block, or Gen III HEMI, this package includes a specially designed torque converter and requires a standalone controller—making it one of the few high-performance GM automatic transmissions available for Mopar engine applications.
Custom-Built, Not Mass-Produced
At Gearstar, every 4L65E is hand-built from start to finish by a single master technician. This hands-on approach ensures complete quality control and unmatched attention to detail. There are no assembly lines—just one expert dedicated to your build from the first bolt to final test.
Before shipping, each unit is dyno-tested for the equivalent of 100 miles. This rigorous process guarantees the transmission is performing flawlessly before it ever leaves the shop—saving you time and hassle during installation.
Perfectly Paired Torque Converter Included
Every Gearstar 4L65E package includes a custom torque converter, engineered specifically for your vehicle’s power level, application, and performance goals. Since acquiring Yank Performance Converters in 2022, Gearstar has brought converter manufacturing entirely in-house, ensuring seamless integration across the engine, transmission, and drivetrain.
Designed to Perform—Built to Last
Gearstar offers several performance levels for both 2WD and 4×4 applications. These range from Level II units rated for up to 400 horsepower to Level IV packages capable of handling 650 horsepower in 2WD or 600 in 4×4 configurations.
Level 2
Power Handling: 400 HP / 400 ft-lbs torque
Torque Converter Stall: Lower stall range (1600–2400 RPM) for smoother street driving
Component Strength: Uses high-energy frictions and a 10-vane pump, suitable for moderate builds
Performance Focus: Optimized for reliability and moderate performance
Level 3
Power Handling: 500 HP / 500 ft-lbs torque
Torque Converter Stall: Higher stall range (2600–3200 RPM) for performance
Component Strength: Upgrades to Raybestos Stage 1 frictions, a 13-vane pump, and a stronger input drum for increased durability
Performance Focus: Balances performance and durability for more demanding applications
Level 4
Power Handling: 650 HP / 600–650 ft-lbs torque
Torque Converter Stall: Highest stall range (2600–4000 RPM) with custom 10” or 11” billet converter for aggressive performance
Component Strength: Incorporates Raybestos Gen II racing frictions, hardened output and reaction shafts, and front/rear 5-pinion planetary sets for maximum strength
Performance Focus: Tailored for high-horsepower street and track use, with the most robust components
Additional Notes
- All levels require an ECU controller and transmission cooler for non-OEM applications.
- Gearstar’s transmissions are custom-built by a single technician and dyno-tested for reliability.
- The 4L65E’s design improvements (e.g., five-pinion planetary carrier, hardened sun shell, 300mm input shaft, and better 3-4 clutch) make it stronger than the 4L60E, with each level enhancing these features for higher performance.
Warranty and Support
Gearstar stands behind its craftsmanship:
- 2WD transmissions come with a 3-year / 36,000-mile warranty
- 4×4 transmissions include a 1-year / 12,000-mile warranty
Their in-house experts are always available to help with installation questions or performance tuning support—part of Gearstar’s commitment to long-term performance and customer satisfaction.
Upgrade with Confidence
The 4L65E represents more than just an evolution of the 4L60E—it’s a proven, high-performance transmission capable of supporting powerful street cars, off-roaders, and classic restorations alike. Built by experts. Dyno-tested. Backed by warranty. And ready to bolt in.
Ready to take your build to the next level? Gearstar has the performance you need—precision-built and track-tested.
