FREE ADAPTER Connectors TO CONVERT HarnessTO EV6 Injectors IF NEEDED. (DRIVE BY WIRE ONLY) WITH 4L60E OR 4L80E TRANSMISSIONS. PARTS INCLUDED: Complete Engine and Transmission Harness, Instruction Manual NOTES: These harnesses are designed for retrofitting '03 - '07 Vortec engines (4.8, 5.3, 6.0-Liter) and 4L60E or 4L80E transmissions into older muscle cars and street rods or newer ehicles. Harness allows use of the factory Vortec intake manifold and multec injectors with flex-fuel injectors (EV6) optional(Ev6 plug and play adapters request in buyer notes). . They are completely plug and play with four wire hookup (switched power, constant power and ground connections required). Harnesses are designed with a sliding grommet seal and 4 - 5 feet of length from the rear of the cylinder head to the PCM mounting position under the vehicle dashboard. A sliding grommet seal allows for professional, leak proof installation. Harnesses are professionally constructed from Brand New Delphi Connectors and TXL (Polyethylene Cross Linked) High Temperature Wire to Specifications. All harnesses are 100% Quality Inspected prior to shipping.