Speartech STE-LS3-4L80 LS3 Crate Powertrain Swap Controls Kit with 4L80E

The Speartech STE-LS3-4L80 is a complete LS Crate Powertrain Swap Controls Kit engineered specifically for the Gen 4 LS3 engine paired with the 4L80E transmission. Designed for LS swap enthusiasts and professional builders alike, this kit takes the guesswork out of wiring your LS3/4L80E powertrain combination with a fully tested, plug-and-play standalone harness solution.

Speartech has been building standalone wiring harnesses for the Gen 4 (58x) LS platform since the engine's inception, making them one of the most experienced names in the LS swap harness industry. Each harness is assembled and tested on a live engine and transmission setup that mirrors real-world swap configurations, ensuring correct connector placement, fit, and function right out of the box.

Once the harness passes all diagnostic run tests, it is finished with Speartech's exclusive heat-resistant woven fabric sleeve — a premium-grade covering that provides durability and a clean, professional appearance.

Key Features:

• Specifically configured for the LS3 engine with 4L80E transmission (Gen 4 / 58x platform)
• Standalone wiring harness — no factory BCM or chassis wiring required
• Every wire individually labeled for straightforward installation
• Includes programmed ECM/TCM modules, all sensors, throttle pedal, and front (pre-cat) O2 sensors
• OBD2 port with integrated check engine light for easy diagnostics
• Heat-resistant woven fabric harness covering for long-term durability
• Built and live-tested on matching engine and transmission hardware before shipping
• Standard harness length designed for ECM mounting inside the vehicle cabin
• No post-cat O2, EVAP, or purge emissions wiring included (clean non-emissions build)

Emissions Note: This product is legal for sale and use on uncontrolled (non-emissions controlled) vehicles only. It is not legal for use on emissions-controlled street vehicles.

The STE-LS3-4L80 delivers everything needed to get your LS3/4L80E swap running reliably, with decades of hands-on LS harness experience built into every connection.