A lot of LS swaps get stymied in an unexpected place: the final precious feet of ignition wiring. That’s because a stock GM LS wiring harness typically uses a pair of standalone sub-harnesses to connect each coil pack back to the main harness. These sub-harnesses are often missing or hacked up in a lot of junkyard LS engine pulls.

Perhaps more importantly, these sub-harnesses can be subject to vibration and intense heat cycles, which accelerates their deterioration—and considering the earliest LS engines are over twenty years old, it means that yours may be due for replacement.

If any of this sounds familiar, then you’ll probably want to hear about the Summit Racing Ignition Coil Wiring Harnesses for GM LS engines.

Heading to a scrapyard to find an LS engine? Start with our LS Engine Spotter’s Guides:
* Part 1: Matching the Vehicle to the Engine
* Part 2: Matching the Engine to the Vehicle

(Image/Summit Racing)

No need to worry about cutting or splicing wires here, these Summit Racing Ignition Coil Wiring Harness are plug-and-play, using the factory connectors to hook right up to stock-style LS ignition coils with coil-on-plug terminals.

Here’s a look at the coil-side connector. (Image/Summit Racing)
And here’s the connector that plugs into the main wiring harness. (Image/Summit Racing)

Each sub-harness is made with longevity in mind, with durable components that’ll stand up to miles of abuse.

Long story short, these harnesses are a smart replacement for a damaged or missing one—and you won’t have to spend a weekend scouring junkyards to find them.

Oh, and if you need the ignition coil harness for the 5.7L LS1 engine found in certain 1999-2005 GM cars like the Corvette, GTO, Camaro/Firebird, and CTS-V, Summit Racing’s got you covered there, too. Check out part number SUM-890107.