What wiring should I plan for a Holley Terminator X on a C3 LS swap?

Here is what the documentation says. Each point links to its source; details depend on your exact computer, harness and transmission.

• Holley kit 550-916 supports 24x LS1/LS6 engines with EV1 injectors and includes electronic transmission control for 4L60E/4L80E with a transmission-control harness in the box. (Holley)
• The Terminator X Max ECU provides four configurable inputs (12V, ground, 5V, frequency) for trans-brake control. (Holley)
• For a non-electronic 700R4 lockup, Holley directs the TCC output through a relay and a separate brake-pedal disable switch. (Documents)
• The neutral safety switch is not related to the Quick 1 controller or harness, but the manual says it should still be wired in every installation. (US Shift)
• The EZ-TCU setup wizard walks through initial setup including TPS calibration. (Static)
• The EZ-TCU speedometer output puts out a 12V square wave to drive an electronic speedometer, with the number of pulses per mile selected in the handheld. (Static)
• Chevrolet Performance kit 19332775 covers GM 4L60E/4L65E/4L70E transmissions from 1993 to 2008, while kit 19332780 covers 4L80E/4L85E transmissions from 1991 to 2008. (Gmspecialtyvehicles)
• Chevrolet Performance notes these transmissions are fully electronic and will not shift automatically without a controller, and a TPS is required because shift points and pressures are derived from throttle opening. (Gmspecialtyvehicles)
• The Holley Terminator X Max transmission harness is part 558-405 and covers pre-2009 4L60E and 4L80E applications, paired with ECU part 554-153. (Manuals)

Confirm against the instructions for your exact parts before wiring. More: Transmission control in our tuning guide.