Holley EFI: Terminator X kits and Dominator

About Holley

Terminator X is the most common way to run an LS or LT swap: an ECU with an engine harness already built for one engine family, a wideband and a handheld touchscreen in the box. The range here covers the LS1/LS6 24x engines, Gen III and Gen IV trucks and the LS2/LS3, and the Gen V LT direct-injection engines, with 4L60E/4L80E transmission control on the Max kits that carry it.

The Dominator is Holley’s race ECU: more inputs and outputs than any Terminator, for builds that have outgrown a kit. Match the kit to your engine’s crank reluctor and throttle type — if you are unsure, call with the engine code before ordering.

Questions before you buy

Terminator X or Terminator X Max?

Max kits add drive-by-wire throttle control and, on the kits listed with it, 4L60E/4L80E transmission control. If your engine has an electronic throttle or you want the ECU to run the automatic, you want a Max kit.

Is DEFI an authorised Holley dealer?

Yes. Every Holley unit here is sold at the price authorised dealers advertise, stocked in Corona, CA, and shipped free in the continental US. Alaska and Hawaii are quoted by phone.

Can you install and tune a Holley ECU?

Yes. We install, wire and calibrate Holley engine management in our Corona shop and tune it on a Mainline ProHub hub dyno, with the full sheet at the end. Shop labor is quoted against your car.

Can I return a Holley ECU?

No. There are no returns or exchanges on third-party hardware once it ships, and the manufacturer’s warranty is the warranty. Call before you order if you are not sure which unit fits.