Handcrafted engine wiring that runs flawless the first time.
Custom standalone harnesses and ECM tuning for GM LS and LT power plants — built one at a time from new color-coded wire and genuine GM terminals, then soldered and blueprinted to your exact combo.
1999
Building since
~400
Harnesses / year
USA
Handcrafted
What we do
Wiring & tuning, done the right way
Pro Wire Harness
Built from scratch in your exact configuration with new wire, genuine GM connectors and terminals. Every crimp is made with GM tooling and then soldered — labeled and ready to drop in.
Learn more →RestoreModification & Repair
Send in your factory GM, Ford, or Duramax harness and computer. We rewire, update, and reprogram it — often saving you real time and money over a full rebuild.
Learn more →SwapLS & Vortec Conversion
Going from a TBI 4.3L truck to an LM7 or LS1? We marry the factory and swap harnesses into one, so the dash, ABS, four-wheel drive, and ECM all keep working together.
Learn more →CalibrationECM Tuning & Programming
The right calibration for your specific setup — engine ECM, pedal, TAC module, and transmission controller, blueprinted together. Your cal-file stays updated for the life of your ECM.
Learn more →On the bench
How every harness is built
Uncompromising quality isn't a slogan here — it's the standard, checked at every termination.
New TXL & GXL wire
Synthetic, low-resistance, color-coded wire throughout — never re-used, never guessed.
Genuine GM connectors & terminals
Real Delphi / ACDelco parts, not knock-off imitations that fail down the road.
Correct GM crimp tooling
A good mechanical crimp made with the right tool on every terminal — the foundation of a harness that lasts.
Every termination soldered
We solder and seal each connection. It's what separates a harness that works from one that runs flawless.
Blueprinted to your combo
Wiring and calibration matched to your exact engine and controllers, so the dash and computers work in harmony.
Simple process
Three steps to a harness that just works
You've got too many options in today's market — from cheap imitations to mass-produced systems that never quite fit. We narrow it down and take it from here.
Send it in
Ship us your factory harness and Delphi / ACDelco computer — or just tell us the engine, transmission, and car you're building, and what you want it to do.
We build & program
We rewire or build from scratch, match the exact calibration for your application, and blueprint the ECM, TAC, and transmission controllers together.
Bolt it in
Your harness ships back labeled and ready. Plug it in, fire it up, and drive — with cal-file support for the life of your ECM behind you.
Custom vs. mass-produced
Why builders choose SSW
Don't base the decision on price alone — you get what you pay for. Here's the honest difference between an assembly line and a bench.
The mass-produced route
- Assembly-line volume
- Thousands of harnesses a year off one line
- Generic cal files that may not match your combo
- Fast, but you adapt your build to the harness
- Support ends once it's in the box
Speed Scene Wiring
- Custom, one at a time
- About 400 harnesses a year — each one custom
- A rare skill-set with a specialty in GM electronics
- Blueprinted to your exact engine and controllers
- We stand behind what we sell — since 1999
In the shop
Parts & materials
The same components that go into our harnesses, available to builders who wire their own.
Automotive Wire
GXL and TXL cross-link wire in a full range of gauges and colors — sold by the foot from 500 ft up to 15,000 ft.
Connectors & Terminals
Genuine Delphi, WeatherPack, and MetriPack connectors and terminals — the exact parts a factory-grade GM harness is built from.
GM Computers & ECMs
ECMs and controllers for LS and LT swaps, matched and available with programming so the module is ready to run your combo.
Speed Sensors
Vehicle and transmission speed sensors to keep your speedometer, ABS, and shift logic reading true after a swap.
Tools, Tape & Loom
Crimp tools, high-temp harness tape, split loom, and the shop supplies you need to build and protect a clean harness.
Technical Help
Schematics, GM ECM part-number references, and straight answers on the power plant or harness you're about to invest in.
Online store — The full parts catalog and checkout are being rebuilt for relaunch. Need something now? Contact us and we'll get it out to you.
Get in touch
Let's build your harness
Tell us the engine, transmission, and car — and what you want it to do. We'll help you narrow it down and quote the build.
Prefer to talk it through? Call 210-370-7791.