Ask most folks who have undertaken an LS Swap—specifically if their swap involved an LS motor sourced from a junkyard—and there’s a good chance they’ll tell you that the wiring was the trickiest part of the job.
That’s why Painless Performance makes new LS-Swap wiring harnesses.
These LS Swap wiring harness eliminate the risks associated with reusing the sketchy, old wiring harness that came with your junkyard LS—we’re talking things like broken wires, torn insulation, and cracked connectors.
And perhaps more importantly, they’ll simplify your LS swap, thanks to clear labeling, easy-to-follow instructions, and intuitive color coding on each wire.
The kits use the factory LS connectors too, so they’re plug-n-play with all the factory sensors and ECU and, better still, each harness is made in the USA and thoroughly tested before it leaves the Painless Performance facility.
We spoke with the Painless team for a bit during a stop on the 2026 Hot Rod Power Tour and they told us these kits are really popular with the restomod crowd, but are equally handy when replacing an LS engine in a late model car, truck, or SUV—particularly a workhorse commuter that’s got a few hundred thousand miles under its belt. After all, wires and connectors have a tendency to wear out with use, which opens the door to all sorts of electrical gremlins when you’re undertaking an invasive job like an engine swap.
Best of all, Painless Performance gives you a ton of options for its LS Swap engine harnesses, to account for factors like drive-by-wire or drive-by-cable throttle bodies, and automatic or manual transmissions.
Click here to see all the Painless Performance Fuel Injection Wiring Harnesses available now at Summit Racing.
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