NOTES: These Harnesses are designed for retrofitting '03 - '07 Vortec engines (4.8, 5.3, 6.0-Liter) and 4L60E transmissions into older muscle cars and street rods. Harness allows use of Injectors (EV6). 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.