Mark Houlahan
Tech Editor, Mustang Monthly
April 21, 2014

When building a dedicated race car for competition use—one that will always be trailered and never be used on the street—it’s imperative that the wiring system not only be kept simple but be easy to access for quick servicing. Using the factory wiring—while an option—is often discouraged due to many factors, including age, weight, routing, and excess circuits that are not needed in a dedicated race car. You can save several pounds by removing the old wiring harness and replacing it with a dedicated race car harness. Not to mention for the Fords we mess with many use ancient glass fuses with not enough circuits to properly control a typical race car’s electronic diet of electric pumps, fans, ignition systems, and more.

Besides the obvious weight savings and modern circuit protection, dedicated race car wiring also allows easier servicing with longer wire lengths to allow the fuse box to be mounted in an easy to access location versus the stock fuse box, which is often buried up under the dash somewhere. Having the fuse box mounted on the trans tunnel, dash, or rollbar means quick access to fuses and relays, which could mean the difference between making the next round and being stuck in the pits while your class makes its runs. Race car wiring systems also feature easy access switch panels for all of the race car’s critical systems, including fuel and water pumps, ignition, lights, and more.

Painless Performance Products is a household name when it comes to automotive wiring. From street rods and kit cars to replacement muscle car harnesses for classic Mustangs and other Fords, Painless has a wiring solution. So it’s no surprise that when it comes to wiring your dedicated race car project that Painless has you covered here as well. Painless offers builders quality race car wiring harnesses and accessories like trunk-mount battery cable kits and more to ensure your race car is wired properly and with the minimum of effort.

The 1967 Fairlane you see here is owned by Rusty Gillis, a former Super Stock racer who at one time held the NHRA SS/GA mph and e.t. records in his ’69 Mustang (featured in Modified Mustangs & Fords way back in our Dec. ’07 issue, you can read the feature story HERE. Rusty’s ’69 Mustang has been restored and the car is too valuable to take down the track anymore, so he decided to build this Fairlane to help him scratch his 1,320 itch. The Fairlane will be FE powered, just like his Mustang. The chassis setup work is complete, the paint is immaculate, and now Rusty is ready to wire the car and install the drivetrain. We’ll be installing the Painless PN 50005 10-circuit race car chassis harness with switch panel for rollbar or in-dash mounting. Check out the captions to see just how easy it is to wire a dedicated race car harness in your project.

1 The Painless 50005 chassis harness features a compact fuse/relay panel that is fully labeled with all circuit information and generous wire lengths. The included switch panel can either be dash mounted or rollbar mounted with the included mounting box (hose clamps not included). Painless provides plenty of tie-wraps, terminals, and a 70-amp main fuse.

2 When you trunk-mount a battery you need some serious cables to carry the electrical load. Painless Performance’s battery cable kit (PN 40100) and ground strap kit (PN 40140) will ensure the starter gets all the power it needs and the battery is properly charged.

3 Besides the main chassis wiring Painless can also provide any electrical or wiring hardware for your wiring project. We ordered some bulk wire lengths for future gauge wiring, a grommet kit (PN 71901), a weatherproof extreme terminal kit (PN 40065), and a Painless Performance’s brand-new roll over wire crimpers for crimping non-insulated terminals (PN 70900).

4 Another new product Painless has just released that we felt would be a perfect complement to the Fairlane’s wiring project is its new Classic Braid Wire Wrap. The “cloth” appearing covering has a nice nostalgic/vintage flair that works well with the car and Painless offers it in a complete chassis kit (PN 70970) with plenty of wire wrap for different harness diameters and even includes shrink wrap and self-vulcanizing tape.